Question 35565: Finite Mapping as a Function

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Original question and givens
Definition and scope
Step-by-step derivation
Reverse checks
Result
This question review and source binding

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R0070-35565 · q-20260913-finite-function-mapping-0020

Original question and givens

Let X={x20-1, x20-2, x20-3, x20-4} and Y={y20-1, y20-2, y20-3, y20-4, y20-5}. The finite correspondence is x20-1↦z20, x20-2↦y20-1, x20-3↦y20-2, x20-4↦y20-3. Does it define a function f:X→Y? Keep the codomain Y distinct from the actual range.

G001 — Let X={x20-1, x20-2, x20-3, x20-4} and Y={y20-1, y20-2, y20-3, y20-4, y20-5}. The finite correspondence is x20-1↦z20, x20-2↦y20-1, x20-3↦y20-2, x20-4↦y20-3. Does it define a function f:X→Y? Keep the codomain Y distinct from the actual range.

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.

mko-function-mapping

Step-by-step derivation

S001 · implies

Before

source roles = [qf-finite-function-mapping, [codomain, domain, pairs, scenario]]

After

derived = [function, null, null]

Conditions: none

Use THIS bank’s actual fields,operation/domain and types.BASE retains permissible extra metadata.Do not import LDL SAFE/set limits or a different bank’s deduplication rules.

Step identifiers and dependencies

Rule: R70_SOURCE_bank_specific_interface · Uses: G001

S002 · implies

Before

source roles = [[x20-1, x20-2, x20-3, x20-4], [y20-1, y20-2, y20-3, y20-4, y20-5], [[x20-1, z20], [x20-2, y20-1], [x20-3, y20-2], [x20-4, y20-3]]]

After

derived = [one RAW assignment per domain input]

Conditions: none

THIS original finite-function bank requires exactly ONE RAW assignment row for every input.Do not borrow another bank’s duplicate-pair normalization.The codomain may exceed the range;check multiplicity,missing inputs and outside values directly.

Step identifiers and dependencies

Rule: Function_ORIGINAL_labels_RAW_rows_NO_legacy_dedup · Uses: G001, S001

S003 · implies

Before

source roles = [0, x20-1, z20]

After

derived = [No]

Conditions: none

Check EACH RAW row for x∈A and y∈B.Retain duplicate rows and row indices;never discard a bad row and then announce a function.

Step identifiers and dependencies

Rule: Function_EACH_RAW_assignment_domain_and_codomain · Uses: G001, S002

S004 · implies

Before

source roles = [1, x20-2, y20-1]

After

derived = [Yes]

Conditions: none

Check EACH RAW row for x∈A and y∈B.Retain duplicate rows and row indices;never discard a bad row and then announce a function.

Step identifiers and dependencies

Rule: Function_EACH_RAW_assignment_domain_and_codomain · Uses: G001, S003

S005 · implies

Before

source roles = [2, x20-3, y20-2]

After

derived = [Yes]

Conditions: none

Check EACH RAW row for x∈A and y∈B.Retain duplicate rows and row indices;never discard a bad row and then announce a function.

Step identifiers and dependencies

Rule: Function_EACH_RAW_assignment_domain_and_codomain · Uses: G001, S004

S006 · implies

Before

source roles = [3, x20-4, y20-3]

After

derived = [Yes]

Conditions: none

Check EACH RAW row for x∈A and y∈B.Retain duplicate rows and row indices;never discard a bad row and then announce a function.

Step identifiers and dependencies

Rule: Function_EACH_RAW_assignment_domain_and_codomain · Uses: G001, S005

S007 · implies

Before

source roles = [x20-1, [z20]]

After

derived = [1, Yes]

Conditions: none

For EVERY domain input,check EXACTLY ONE RAW assignment.Missing inputs fail;even two identical-output rows cannot silently deduplicate in this ORIGINAL contract.

Step identifiers and dependencies

Rule: Function_EACH_input_exactly_ONE_RAW_row · Uses: G001, S006

S008 · implies

Before

source roles = [x20-2, [y20-1]]

After

derived = [1, Yes]

Conditions: none

For EVERY domain input,check EXACTLY ONE RAW assignment.Missing inputs fail;even two identical-output rows cannot silently deduplicate in this ORIGINAL contract.

Step identifiers and dependencies

Rule: Function_EACH_input_exactly_ONE_RAW_row · Uses: G001, S007

S009 · implies

Before

source roles = [x20-3, [y20-2]]

After

derived = [1, Yes]

Conditions: none

For EVERY domain input,check EXACTLY ONE RAW assignment.Missing inputs fail;even two identical-output rows cannot silently deduplicate in this ORIGINAL contract.

Step identifiers and dependencies

Rule: Function_EACH_input_exactly_ONE_RAW_row · Uses: G001, S008

S010 · implies

Before

source roles = [x20-4, [y20-3]]

After

derived = [1, Yes]

Conditions: none

For EVERY domain input,check EXACTLY ONE RAW assignment.Missing inputs fail;even two identical-output rows cannot silently deduplicate in this ORIGINAL contract.

Step identifiers and dependencies

Rule: Function_EACH_input_exactly_ONE_RAW_row · Uses: G001, S009

S011 · implies

Before

source roles = [[], [], [[0, x20-1, z20]], [y20-1, y20-2, y20-3, z20], [y20-1, y20-2, y20-3, y20-4, y20-5]]

After

derived = [No]

Conditions: none

A function A→B requires absence of ALL three violations.Different inputs may share an output;injectivity/surjectivity is not required.The actual range does not replace the declared B.

Step identifiers and dependencies

Rule: Function_COMPLETE_total_single_valued_into_declared_codomain · Uses: G001, S010

Reverse checks

S011 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
S010 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
S009 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
S008 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
S007 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
S006 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
S005 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
S004 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
S003 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
S002 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
S001 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.

Result

No

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: 8fde63a7447634764469b82119229b2bf4a80f8bd03851f4d0de5fb6b50eec12
candidate record SHA-256: ed44069248b14a6207e528ce96f17e6dee734fadb24d89d4308f4de7cef4687b
semantic review receipt SHA-256: 9820ac6529139bd53d516c8bfdfdd41184b0cd52dad69fa433344010db37af80
question-first witness SHA-256: c9c939762bbd4d3ea3403084c8e95541dc2c7e56eb82fc74eaba8c80a4517dab
Lean: NOT_RUN · human review: NOT_PERFORMED

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