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Question 19423: Exact Chromatic Number Needs Both Lower and Upper Evidence

On this page
  1. Original question and givens
  2. Definition and scope
  3. Step-by-step derivation
  4. Reverse checks
  5. Result
  6. This question review and source binding

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R0037-19423 · q-20261014-advance-20261106-r01-chromatic-number-0073

Original question and givens

Use the complete finite loop-free simple undirected graph on Fin(6)={0,…,5} with canonical edges=[[0, 1], [0, 3], [0, 5], [1, 2], [1, 3], [2, 3], [2, 5], [3, 4], [4, 5]]. All graph vertices and edges are supplied, and exact searches are limited to n≤9. Give (chromatic_number, canonical_coloring, lower_bound_exhausted, certificate).

  • G001 — Use the complete finite loop-free simple undirected graph on Fin(6)={0,…,5} with canonical edges=[[0, 1], [0, 3], [0, 5], [1, 2], [1, 3], [2, 3], [2, 5], [3, 4], [4, 5]]. All graph vertices and edges are supplied, and exact searches are limited to n≤9. Give (chromatic_number, canonical_coloring, lower_bound_exhausted, certificate).

Definition and scope

Use the original question domain, assumptions and cited MKO definitions. This item has second-context mathematical and bilingual review, with the model, answer and every arithmetic step independently recomputed from the original parameters; the source question remains a candidate.

Step-by-step derivation

S001 · implies

Before

source operation=chromatic-exact-number;original snapshot and mathematics retained

After

explicit ordered source output fields=[chromatic_number, canonical_coloring, lower_bound_exhausted, certificate]

Conditions: none

Retain the historical interface marker in the original snapshot while listing ordered source fields here,without JavaScript or external lookup.Field names are not mathematical evidence,and No retains the operation's specific claim scope.

Step identifiers and dependencies

Rule: source_ordered_interface_explicit_without_javascript · Uses: G001

S002 · implies

Before

ACTUAL complete finite carrier Fin(6);ALL original canonical simple undirected edges=[[0, 1], [0, 3], [0, 5], [1, 2], [1, 3], [2, 3], [2, 5], [3, 4], [4, 5]]

After

use full original vertex/edge data;exact search domain n<=9;empty carrier and isolated vertices RETAINED

Conditions: none

Retain every original vertex and edge.This family includes n=0 rather than importing a previous nonempty-carrier guard or deleting isolates.Actual palette labels must not be replaced by semantic relabeling.

Step identifiers and dependencies

Rule: chromatic_complete_graph_not_semantic_color_relabeling · Uses: G001, S001

S003 · implies

Before

ACTUAL graph Fin(6);try palette[0,1);original vertex order0..5

After

search ALL earlier lexicographic prefixes:vertex order fixed,each color tried increasingly;only an actual earlier-edge conflict may prune

Conditions: none

Search each k completely rather than treating a failed greedy run as non-colorability.Fixed original vertex order and increasing colors define the source's first lexicographic witness.Prune only an actual edge conflict;otherwise continue or exhaustively backtrack.

Step identifiers and dependencies

Rule: chromatic_complete_lex_search_not_greedy_optimality · Uses: G001, S002

S004 · implies

Before

palette=1;original vertex=0;assigned ORIGINAL prefix=[];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[];admissible extension=Yes

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S003

S005 · implies

Before

palette=1;original vertex=1;assigned ORIGINAL prefix=[0];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[0];admissible extension=No

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S004

S006 · implies

Before

palette=1;original vertex=1;original fixed prefix=[0];ALL colors0..0 attempted

After

no valid completion of this prefix in this palette

Conditions: none

All allowed labels at this vertex have been tried,so this fixed prefix has no completion.Only this conclusion at the root excludes the whole k-palette.

Step identifiers and dependencies

Rule: chromatic_full_palette_exhaustion_at_prefix · Uses: G001, S005

S007 · implies

Before

palette=1;original prefix=[];vertex=0;chosen color=0;ALL its later completions exhausted

After

restore this unassigned coordinate and try the next ascending color

Conditions: none

Backtrack only after the whole subtree fails.Every later completion of this branch was excluded by an actual conflict or a completely exhausted subtree,not one sampled attempt.

Step identifiers and dependencies

Rule: chromatic_exhausted_branch_backtracking_not_one_bad_sample · Uses: G001, S006

S008 · implies

Before

palette=1;original vertex=0;original fixed prefix=[];ALL colors0..0 attempted

After

no valid completion of this prefix in this palette

Conditions: none

All allowed labels at this vertex have been tried,so this fixed prefix has no completion.Only this conclusion at the root excludes the whole k-palette.

Step identifiers and dependencies

Rule: chromatic_full_palette_exhaustion_at_prefix · Uses: G001, S007

S009 · implies

Before

palette[0,1) searched from EMPTY root prefix with full branch exclusions

After

NO proper coloring exists in this palette;any smaller palette is a subset of it

Conditions: none

Exhausting the complete root tree supplies the lower certificate.Any smaller palette embeds in this one and is excluded as well;no greedy path establishes this conclusion.

Step identifiers and dependencies

Rule: chromatic_actual_lower_palette_exhaustion · Uses: G001, S008

S010 · implies

Before

ACTUAL graph Fin(6);try palette[0,2);original vertex order0..5

After

search ALL earlier lexicographic prefixes:vertex order fixed,each color tried increasingly;only an actual earlier-edge conflict may prune

Conditions: none

Search each k completely rather than treating a failed greedy run as non-colorability.Fixed original vertex order and increasing colors define the source's first lexicographic witness.Prune only an actual edge conflict;otherwise continue or exhaustively backtrack.

Step identifiers and dependencies

Rule: chromatic_complete_lex_search_not_greedy_optimality · Uses: G001, S009

S011 · implies

Before

palette=2;original vertex=0;assigned ORIGINAL prefix=[];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[];admissible extension=Yes

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S010

S012 · implies

Before

palette=2;original vertex=1;assigned ORIGINAL prefix=[0];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[0];admissible extension=No

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S011

S013 · implies

Before

palette=2;original vertex=1;assigned ORIGINAL prefix=[0];try next ascending color=1

After

ALL earlier adjacent vertices already using this label=[];admissible extension=Yes

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S012

S014 · implies

Before

palette=2;original vertex=2;assigned ORIGINAL prefix=[0, 1];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[];admissible extension=Yes

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S013

S015 · implies

Before

palette=2;original vertex=3;assigned ORIGINAL prefix=[0, 1, 0];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[0, 2];admissible extension=No

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S014

S016 · implies

Before

palette=2;original vertex=3;assigned ORIGINAL prefix=[0, 1, 0];try next ascending color=1

After

ALL earlier adjacent vertices already using this label=[1];admissible extension=No

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S015

S017 · implies

Before

palette=2;original vertex=3;original fixed prefix=[0, 1, 0];ALL colors0..1 attempted

After

no valid completion of this prefix in this palette

Conditions: none

All allowed labels at this vertex have been tried,so this fixed prefix has no completion.Only this conclusion at the root excludes the whole k-palette.

Step identifiers and dependencies

Rule: chromatic_full_palette_exhaustion_at_prefix · Uses: G001, S016

S018 · implies

Before

palette=2;original prefix=[0, 1];vertex=2;chosen color=0;ALL its later completions exhausted

After

restore this unassigned coordinate and try the next ascending color

Conditions: none

Backtrack only after the whole subtree fails.Every later completion of this branch was excluded by an actual conflict or a completely exhausted subtree,not one sampled attempt.

Step identifiers and dependencies

Rule: chromatic_exhausted_branch_backtracking_not_one_bad_sample · Uses: G001, S017

S019 · implies

Before

palette=2;original vertex=2;assigned ORIGINAL prefix=[0, 1];try next ascending color=1

After

ALL earlier adjacent vertices already using this label=[1];admissible extension=No

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S018

S020 · implies

Before

palette=2;original vertex=2;original fixed prefix=[0, 1];ALL colors0..1 attempted

After

no valid completion of this prefix in this palette

Conditions: none

All allowed labels at this vertex have been tried,so this fixed prefix has no completion.Only this conclusion at the root excludes the whole k-palette.

Step identifiers and dependencies

Rule: chromatic_full_palette_exhaustion_at_prefix · Uses: G001, S019

S021 · implies

Before

palette=2;original prefix=[0];vertex=1;chosen color=1;ALL its later completions exhausted

After

restore this unassigned coordinate and try the next ascending color

Conditions: none

Backtrack only after the whole subtree fails.Every later completion of this branch was excluded by an actual conflict or a completely exhausted subtree,not one sampled attempt.

Step identifiers and dependencies

Rule: chromatic_exhausted_branch_backtracking_not_one_bad_sample · Uses: G001, S020

S022 · implies

Before

palette=2;original vertex=1;original fixed prefix=[0];ALL colors0..1 attempted

After

no valid completion of this prefix in this palette

Conditions: none

All allowed labels at this vertex have been tried,so this fixed prefix has no completion.Only this conclusion at the root excludes the whole k-palette.

Step identifiers and dependencies

Rule: chromatic_full_palette_exhaustion_at_prefix · Uses: G001, S021

S023 · implies

Before

palette=2;original prefix=[];vertex=0;chosen color=0;ALL its later completions exhausted

After

restore this unassigned coordinate and try the next ascending color

Conditions: none

Backtrack only after the whole subtree fails.Every later completion of this branch was excluded by an actual conflict or a completely exhausted subtree,not one sampled attempt.

Step identifiers and dependencies

Rule: chromatic_exhausted_branch_backtracking_not_one_bad_sample · Uses: G001, S022

S024 · implies

Before

palette=2;original vertex=0;assigned ORIGINAL prefix=[];try next ascending color=1

After

ALL earlier adjacent vertices already using this label=[];admissible extension=Yes

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S023

S025 · implies

Before

palette=2;original vertex=1;assigned ORIGINAL prefix=[1];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[];admissible extension=Yes

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S024

S026 · implies

Before

palette=2;original vertex=2;assigned ORIGINAL prefix=[1, 0];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[1];admissible extension=No

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S025

S027 · implies

Before

palette=2;original vertex=2;assigned ORIGINAL prefix=[1, 0];try next ascending color=1

After

ALL earlier adjacent vertices already using this label=[];admissible extension=Yes

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S026

S028 · implies

Before

palette=2;original vertex=3;assigned ORIGINAL prefix=[1, 0, 1];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[1];admissible extension=No

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S027

S029 · implies

Before

palette=2;original vertex=3;assigned ORIGINAL prefix=[1, 0, 1];try next ascending color=1

After

ALL earlier adjacent vertices already using this label=[0, 2];admissible extension=No

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S028

S030 · implies

Before

palette=2;original vertex=3;original fixed prefix=[1, 0, 1];ALL colors0..1 attempted

After

no valid completion of this prefix in this palette

Conditions: none

All allowed labels at this vertex have been tried,so this fixed prefix has no completion.Only this conclusion at the root excludes the whole k-palette.

Step identifiers and dependencies

Rule: chromatic_full_palette_exhaustion_at_prefix · Uses: G001, S029

S031 · implies

Before

palette=2;original prefix=[1, 0];vertex=2;chosen color=1;ALL its later completions exhausted

After

restore this unassigned coordinate and try the next ascending color

Conditions: none

Backtrack only after the whole subtree fails.Every later completion of this branch was excluded by an actual conflict or a completely exhausted subtree,not one sampled attempt.

Step identifiers and dependencies

Rule: chromatic_exhausted_branch_backtracking_not_one_bad_sample · Uses: G001, S030

S032 · implies

Before

palette=2;original vertex=2;original fixed prefix=[1, 0];ALL colors0..1 attempted

After

no valid completion of this prefix in this palette

Conditions: none

All allowed labels at this vertex have been tried,so this fixed prefix has no completion.Only this conclusion at the root excludes the whole k-palette.

Step identifiers and dependencies

Rule: chromatic_full_palette_exhaustion_at_prefix · Uses: G001, S031

S033 · implies

Before

palette=2;original prefix=[1];vertex=1;chosen color=0;ALL its later completions exhausted

After

restore this unassigned coordinate and try the next ascending color

Conditions: none

Backtrack only after the whole subtree fails.Every later completion of this branch was excluded by an actual conflict or a completely exhausted subtree,not one sampled attempt.

Step identifiers and dependencies

Rule: chromatic_exhausted_branch_backtracking_not_one_bad_sample · Uses: G001, S032

S034 · implies

Before

palette=2;original vertex=1;assigned ORIGINAL prefix=[1];try next ascending color=1

After

ALL earlier adjacent vertices already using this label=[0];admissible extension=No

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S033

S035 · implies

Before

palette=2;original vertex=1;original fixed prefix=[1];ALL colors0..1 attempted

After

no valid completion of this prefix in this palette

Conditions: none

All allowed labels at this vertex have been tried,so this fixed prefix has no completion.Only this conclusion at the root excludes the whole k-palette.

Step identifiers and dependencies

Rule: chromatic_full_palette_exhaustion_at_prefix · Uses: G001, S034

S036 · implies

Before

palette=2;original prefix=[];vertex=0;chosen color=1;ALL its later completions exhausted

After

restore this unassigned coordinate and try the next ascending color

Conditions: none

Backtrack only after the whole subtree fails.Every later completion of this branch was excluded by an actual conflict or a completely exhausted subtree,not one sampled attempt.

Step identifiers and dependencies

Rule: chromatic_exhausted_branch_backtracking_not_one_bad_sample · Uses: G001, S035

S037 · implies

Before

palette=2;original vertex=0;original fixed prefix=[];ALL colors0..1 attempted

After

no valid completion of this prefix in this palette

Conditions: none

All allowed labels at this vertex have been tried,so this fixed prefix has no completion.Only this conclusion at the root excludes the whole k-palette.

Step identifiers and dependencies

Rule: chromatic_full_palette_exhaustion_at_prefix · Uses: G001, S036

S038 · implies

Before

palette[0,2) searched from EMPTY root prefix with full branch exclusions

After

NO proper coloring exists in this palette;any smaller palette is a subset of it

Conditions: none

Exhausting the complete root tree supplies the lower certificate.Any smaller palette embeds in this one and is excluded as well;no greedy path establishes this conclusion.

Step identifiers and dependencies

Rule: chromatic_actual_lower_palette_exhaustion · Uses: G001, S037

S039 · implies

Before

ACTUAL graph Fin(6);try palette[0,3);original vertex order0..5

After

search ALL earlier lexicographic prefixes:vertex order fixed,each color tried increasingly;only an actual earlier-edge conflict may prune

Conditions: none

Search each k completely rather than treating a failed greedy run as non-colorability.Fixed original vertex order and increasing colors define the source's first lexicographic witness.Prune only an actual edge conflict;otherwise continue or exhaustively backtrack.

Step identifiers and dependencies

Rule: chromatic_complete_lex_search_not_greedy_optimality · Uses: G001, S038

S040 · implies

Before

palette=3;original vertex=0;assigned ORIGINAL prefix=[];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[];admissible extension=Yes

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S039

S041 · implies

Before

palette=3;original vertex=1;assigned ORIGINAL prefix=[0];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[0];admissible extension=No

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S040

S042 · implies

Before

palette=3;original vertex=1;assigned ORIGINAL prefix=[0];try next ascending color=1

After

ALL earlier adjacent vertices already using this label=[];admissible extension=Yes

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S041

S043 · implies

Before

palette=3;original vertex=2;assigned ORIGINAL prefix=[0, 1];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[];admissible extension=Yes

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S042

S044 · implies

Before

palette=3;original vertex=3;assigned ORIGINAL prefix=[0, 1, 0];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[0, 2];admissible extension=No

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S043

S045 · implies

Before

palette=3;original vertex=3;assigned ORIGINAL prefix=[0, 1, 0];try next ascending color=1

After

ALL earlier adjacent vertices already using this label=[1];admissible extension=No

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S044

S046 · implies

Before

palette=3;original vertex=3;assigned ORIGINAL prefix=[0, 1, 0];try next ascending color=2

After

ALL earlier adjacent vertices already using this label=[];admissible extension=Yes

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S045

S047 · implies

Before

palette=3;original vertex=4;assigned ORIGINAL prefix=[0, 1, 0, 2];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[];admissible extension=Yes

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S046

S048 · implies

Before

palette=3;original vertex=5;assigned ORIGINAL prefix=[0, 1, 0, 2, 0];try next ascending color=0

After

ALL earlier adjacent vertices already using this label=[0, 2, 4];admissible extension=No

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S047

S049 · implies

Before

palette=3;original vertex=5;assigned ORIGINAL prefix=[0, 1, 0, 2, 0];try next ascending color=1

After

ALL earlier adjacent vertices already using this label=[];admissible extension=Yes

Conditions: none

List all actual earlier-neighbor conflicts for this prefix/color.A conflict rejects every completion of that extension;otherwise recursively check all remaining vertices rather than calling a local pass a complete solution.

Step identifiers and dependencies

Rule: chromatic_every_prefix_color_conflict_or_recursion · Uses: G001, S048

S050 · implies

Before

FIRST completed vertex-order increasing-color search witness=[0, 1, 0, 2, 0, 1];palette size=3;ALL smaller palettes exhausted

After

every ORIGINAL edge endpoints different;constructive chi<= 3 and exhaustive chi>= 3;chi=3;first LEX witness retained

Conditions: none

The complete proper original-edge coloring gives the upper bound;the preceding exhaustive failures give the lower bound.Their equality establishes the exact minimum.Fixed DFS order preserves the source's first lexicographic witness,not an arbitrary optimum.A nonempty edgeless graph succeeds first at k=1 with all zeros;no fictitious0-color search is needed.

Step identifiers and dependencies

Rule: chromatic_constructive_upper_and_exhausted_lower_tie_order · Uses: G001, S049

Reverse checks

  • S050 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S049 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S048 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S047 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S046 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S045 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S044 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S043 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S042 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S041 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S040 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S039 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S038 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S037 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S036 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S035 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S034 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S033 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S032 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S031 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S030 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S029 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S028 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S027 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S026 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S025 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S024 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S023 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S022 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S021 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S020 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S019 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S018 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S017 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S016 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S015 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S014 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S013 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S012 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S011 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S010 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S009 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S008 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S007 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S006 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S005 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S004 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S003 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S002 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S001 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.

Result

(3, [0, 1, 0, 2, 0, 1], Yes, exhaustive_lower_and_constructive_upper_certificates)

The full substitutions and premise checks give the original answer; source identity,format and status are unchanged.

This question review and source binding

Review date: 2026-10-26

Original questions, answers, step expressions, numeric ASTs and historical records are retained. Source candidate labels remain historical and are not overwritten as formal proof.

Source hashes and review receipts
  • input commit: 0f7be61e2c22317a4075561dc822c87d881a50db
  • original question SHA-256: a0b0af2064d5dff1156db2dee383459ddad50d23874c61476fb9cb7dc55a8428
  • candidate record SHA-256: ff9e094255814e2c0ca6d10ec31ecc57f1a36a76c5417a78a04cc1007a760eb2
  • semantic review receipt SHA-256: 065507b602ceee60cf47a700d387a51940e0c6724c35a3336a7a7948a199ed80
  • question-first witness SHA-256: 7203f33b030792559673b0fee520a8c0e70903c4dd970b35293aa40852f333d6
  • Lean: NOT_RUN · human review: NOT_PERFORMED
Same-source full JSON