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Question 35307: Coverage after a Valid Codomain Change

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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R0069-35307 · q-20261004-advance-20261005-r02-surjective-0082

Original question and givens

The declared total function f:A→B has A={-2, -1, 0}, B={1, 3, 5, 7}, and table {(-2, 1), (-1, 3), (0, 5)}. The new codomain B2={1, 3, 5} contains every attained output. Is the same output table surjective as A→B2?

  • G001 — The declared total function f:A→B has A={-2, -1, 0}, B={1, 3, 5, 7}, and table {(-2, 1), (-1, 3), (0, 5)}. The new codomain B2={1, 3, 5} contains every attained output. Is the same output table surjective as A→B2?

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 roles = [qf-surjective-codomain-change, [A, B, B2, operation, pairs]]

After

derived = [changed_codomain, no-invented-domain]

Conditions: none

Keep EACH bank’s keys/operation/domain distinct:LDL/PULSE/function legacy table underscores,TREE full tree_* with its declared domain,and permissive BASE signed without invented op/domain.All arithmetic respects the binary-primitive contract.

Step identifiers and dependencies

Rule: R69_SOURCE_specific_keys_operation_domain_AND_binary_contract · Uses: G001

S002 · implies

Before

source roles = [function ORIGINAL A, 100, [-2, -1, 0]]

After

derived = [[-2, -1, 0]]

Conditions: none

Type EVERY RAW SAFE label,distinctness and THIS bank’s cardinality bound;empty is allowed.Sort ONLY the derived representation,not original JSON.Do not exchange TREE and LDL limits.

Step identifiers and dependencies

Rule: Finite_RAW_ALL_SAFE_distinct_labels_then_derived_sort · Uses: G001, S001

S003 · implies

Before

source roles = [function ORIGINAL B, 100, [1, 3, 5, 7]]

After

derived = [[1, 3, 5, 7]]

Conditions: none

Type EVERY RAW SAFE label,distinctness and THIS bank’s cardinality bound;empty is allowed.Sort ONLY the derived representation,not original JSON.Do not exchange TREE and LDL limits.

Step identifiers and dependencies

Rule: Finite_RAW_ALL_SAFE_distinct_labels_then_derived_sort · Uses: G001, S002

S004 · implies

Before

source roles = [function ORIGINAL table, 0, [-2, 1]]

After

derived = [[-2, 1]]

Conditions: none

BEFORE deduplication,type EACH RAW pair as EXACTLY TWO SAFE components.Identical rows may be representation duplicates,but no unvalidated cell may be silently discarded.

Step identifiers and dependencies

Rule: Pairs_EVERY_RAW_two_SAFE_cells_BEFORE_any_dedup · Uses: G001, S003

S005 · implies

Before

source roles = [function ORIGINAL table, 1, [-1, 3]]

After

derived = [[-1, 3]]

Conditions: none

BEFORE deduplication,type EACH RAW pair as EXACTLY TWO SAFE components.Identical rows may be representation duplicates,but no unvalidated cell may be silently discarded.

Step identifiers and dependencies

Rule: Pairs_EVERY_RAW_two_SAFE_cells_BEFORE_any_dedup · Uses: G001, S004

S006 · implies

Before

source roles = [function ORIGINAL table, 2, [0, 5]]

After

derived = [[0, 5]]

Conditions: none

BEFORE deduplication,type EACH RAW pair as EXACTLY TWO SAFE components.Identical rows may be representation duplicates,but no unvalidated cell may be silently discarded.

Step identifiers and dependencies

Rule: Pairs_EVERY_RAW_two_SAFE_cells_BEFORE_any_dedup · Uses: G001, S005

S007 · implies

Before

source roles = [[-2, -1, 0], [1, 3, 5, 7], [[-2, 1], [-1, 3], [0, 5]]]

After

derived = [Yes]

Conditions: none

FIRST qualify the WHOLE total function A→B:EXACTLY one output for EVERY A and all pairs in A×B.Identical repeated rows normalize in THIS legacy bank,unlike a different PULSE table rule.Qualify ORIGINAL B even for later codomain changes.

Step identifiers and dependencies

Rule: Function_WHOLE_qualified_total_AtoB_before_SURJECTIVE_claim · Uses: G001, S006

S008 · implies

Before

source roles = [function NEW codomain B2, 100, [1, 3, 5]]

After

derived = [[1, 3, 5]]

Conditions: none

Type EVERY RAW SAFE label,distinctness and THIS bank’s cardinality bound;empty is allowed.Sort ONLY the derived representation,not original JSON.Do not exchange TREE and LDL limits.

Step identifiers and dependencies

Rule: Finite_RAW_ALL_SAFE_distinct_labels_then_derived_sort · Uses: G001, S007

S009 · implies

Before

source roles = [[1, 3, 5, 7], [1, 3, 5], [[-2, 1], [-1, 3], [0, 5]]]

After

derived = [Yes]

Conditions: none

FIRST require B2 to contain the ENTIRE attained range for the same table to remain a total function.It may add/remove unattained targets and need not contain ALL old B.Never discard an actual output to force surjectivity.

Step identifiers and dependencies

Rule: Surjective_NEW_codomain_contains_WHOLE_range_not_oldB_required · Uses: G001, S008

S010 · implies

Before

source roles = [NEW B2, -2, 1, 1]

After

derived = [Yes]

Conditions: none

Compare EVERY permitted input’s output with THIS target.List EACH fiber completely;do not confuse target/input or infer surjectivity from cardinalities alone.

Step identifiers and dependencies

Rule: Surjective_EVERY_source_target_fiber_comparison · Uses: G001, S009

S011 · implies

Before

source roles = [NEW B2, -1, 3, 1]

After

derived = [No]

Conditions: none

Compare EVERY permitted input’s output with THIS target.List EACH fiber completely;do not confuse target/input or infer surjectivity from cardinalities alone.

Step identifiers and dependencies

Rule: Surjective_EVERY_source_target_fiber_comparison · Uses: G001, S010

S012 · implies

Before

source roles = [NEW B2, 0, 5, 1]

After

derived = [No]

Conditions: none

Compare EVERY permitted input’s output with THIS target.List EACH fiber completely;do not confuse target/input or infer surjectivity from cardinalities alone.

Step identifiers and dependencies

Rule: Surjective_EVERY_source_target_fiber_comparison · Uses: G001, S011

S013 · implies

Before

source roles = [NEW B2, -2, 1, 3]

After

derived = [No]

Conditions: none

Compare EVERY permitted input’s output with THIS target.List EACH fiber completely;do not confuse target/input or infer surjectivity from cardinalities alone.

Step identifiers and dependencies

Rule: Surjective_EVERY_source_target_fiber_comparison · Uses: G001, S012

S014 · implies

Before

source roles = [NEW B2, -1, 3, 3]

After

derived = [Yes]

Conditions: none

Compare EVERY permitted input’s output with THIS target.List EACH fiber completely;do not confuse target/input or infer surjectivity from cardinalities alone.

Step identifiers and dependencies

Rule: Surjective_EVERY_source_target_fiber_comparison · Uses: G001, S013

S015 · implies

Before

source roles = [NEW B2, 0, 5, 3]

After

derived = [No]

Conditions: none

Compare EVERY permitted input’s output with THIS target.List EACH fiber completely;do not confuse target/input or infer surjectivity from cardinalities alone.

Step identifiers and dependencies

Rule: Surjective_EVERY_source_target_fiber_comparison · Uses: G001, S014

S016 · implies

Before

source roles = [NEW B2, -2, 1, 5]

After

derived = [No]

Conditions: none

Compare EVERY permitted input’s output with THIS target.List EACH fiber completely;do not confuse target/input or infer surjectivity from cardinalities alone.

Step identifiers and dependencies

Rule: Surjective_EVERY_source_target_fiber_comparison · Uses: G001, S015

S017 · implies

Before

source roles = [NEW B2, -1, 3, 5]

After

derived = [No]

Conditions: none

Compare EVERY permitted input’s output with THIS target.List EACH fiber completely;do not confuse target/input or infer surjectivity from cardinalities alone.

Step identifiers and dependencies

Rule: Surjective_EVERY_source_target_fiber_comparison · Uses: G001, S016

S018 · implies

Before

source roles = [NEW B2, 0, 5, 5]

After

derived = [Yes]

Conditions: none

Compare EVERY permitted input’s output with THIS target.List EACH fiber completely;do not confuse target/input or infer surjectivity from cardinalities alone.

Step identifiers and dependencies

Rule: Surjective_EVERY_source_target_fiber_comparison · Uses: G001, S017

S019 · implies

Before

source roles = [[-2, -1, 0], [1, 3, 5], [[1, [-2]], [3, [-1]], [5, [0]]]]

After

derived = [[], Yes]

Conditions: none

Surjectivity requires a preimage for EVERY declared target;multiple preimages are allowed.For a QUALIFIED empty function,the empty-codomain condition is vacuous.The missing set is B(or B2)minus range,not a replacement of the ORIGINAL codomain.

Step identifiers and dependencies

Rule: Surjective_ALL_codomain_targets_covered_including_EMPTY_vacuity · Uses: G001, S018

Reverse checks

  • S019 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S018 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S017 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S016 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S015 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S014 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S013 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S012 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S011 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S010 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S009 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S008 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S007 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S006 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S005 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S004 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S003 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S002 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S001 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.

Result

Yes

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: fa24577646d04c819b7c3c46abe767b4c7e46ea39306e397db748117ea355a28
  • candidate record SHA-256: b27e6a3a85932a6c218b75e1cc8e3139540532fda0813481e93ae45d4903990e
  • semantic review receipt SHA-256: ccf93c72638d6abf6a412514da5838d55ecb09b71d0e4fdec2b559dc9fdee14b
  • question-first witness SHA-256: 11af9a338b5a610342b2cfb2ee295683131b3139ac402dd19b1ba1725976d518
  • Lean: NOT_RUN · human review: NOT_PERFORMED
Same-source full JSON