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Question 7251: Two Typed Codomain Candidates and Their Preimages

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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R0013-07251 · q-20261011-advance-20261015-r03-domain-codomain-range-0026

Original question and givens

Fin(0)=∅ is the source and Fin(0)=∅ the codomain; complete typed images=[] are indexed from 0. All entries must be typed, even unused ones. Ordered codomain candidates=[0, -1]. Give (candidate-type eligibility, preimage index lists or outside-codomain, sizes or outside-codomain). An outside value is not a legal empty preimage.

  • G001 — Fin(0)=∅ is the source and Fin(0)=∅ the codomain; complete typed images=[] are indexed from 0. All entries must be typed, even unused ones. Ordered codomain candidates=[0, -1]. Give (candidate-type eligibility, preimage index lists or outside-codomain, sizes or outside-codomain). An outside value is not a legal empty preimage.

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

declared types Fin(0)→Fin(0);0-based source labels

After

domain,codomain and actual range remain distinct

Conditions: none

Fin(0) is empty;a complete total table is not a partial program function,and its actual range need not equal its declared codomain.This audits finite data,not general infinite-set theorems.

Step identifiers and dependencies

Rule: typed_domain_codomain_data_scope · Uses: G001

S002 · implies

Before

target candidate=0;inside Fin(0)=No

After

preimage=outside the codomain;size/status=outside the codomain

Conditions: none

A legal but unhit codomain value has empty preimage of size0.An outside-codomain candidate is not a legal empty-preimage query in this typed interface.

Step identifiers and dependencies

Rule: typed_preimage_codomain_guard · Uses: G001, S001

S003 · implies

Before

target candidate=-1;inside Fin(0)=No

After

preimage=outside the codomain;size/status=outside the codomain

Conditions: none

A legal but unhit codomain value has empty preimage of size0.An outside-codomain candidate is not a legal empty-preimage query in this typed interface.

Step identifiers and dependencies

Rule: typed_preimage_codomain_guard · Uses: G001, S002

Reverse checks

  • 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

([No, No], [outside-codomain, outside-codomain], [outside-codomain, outside-codomain])

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: 288d9d38fb9841f04fb9ac191c939ac9562c92d17856da35a9ed06e972b9f4ef
  • candidate record SHA-256: bcbcad4957fe98db6cad81dab4e79bc9691e256632495d36dd5b1e6df43705c1
  • semantic review receipt SHA-256: e89fc6d4a50a4a7fc942c6c8939a92f835e30105a9a5850e37dd198f31c1ed59
  • question-first witness SHA-256: 0e1039f4cf022bf35af4e5531651c9a2b7ca7a5fdacac34fb1e4bcd9a81f6299
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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