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Question 14871: A Larger Finite Source Rules Out Every Injection

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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R0028-14871 · q-20261014-advance-20261030-r05-cardinality-comparison-0096

Original question and givens

Use the complete finite source=[200, 201] and target=[300, 301, 302] as distinct-element lists in their original orders. A mapping must be total on that exact source and every image must belong to that exact target. Injectivity and surjectivity are independent mapping properties, not guesses from equal list lengths. The comparison certificates here are finite-only; no unrestricted infinite-set or choice conclusion is inferred. No mapping is supplied in this family. Give (source_size,target_size,larger?,conclusion). conclusion is no_injection_finite_pigeonhole or no_impossibility_certificate.

  • G001 — Use the complete finite source=[200, 201] and target=[300, 301, 302] as distinct-element lists in their original orders. A mapping must be total on that exact source and every image must belong to that exact target. Injectivity and surjectivity are independent mapping properties, not guesses from equal list lengths. The comparison certificates here are finite-only; no unrestricted infinite-set or choice conclusion is inferred. No mapping is supplied in this family. Give (source_size,target_size,larger?,conclusion). conclusion is no_injection_finite_pigeonhole or no_impossibility_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

raw source list=[200, 201];raw target list=[300, 301, 302]

After

distinct finite source=[200, 201];target=[300, 301, 302];sizes=[2, 3]

Conditions: none

This family compares set cardinalities,so repetitions do not add elements.No particular mapping is supplied,and no specific collision pair is invented.

Step identifiers and dependencies

Rule: pigeonhole_set_counts_not_list_multiplicity · Uses: G001

S002 · implies

Before

finite sizes source=2;target=3

After

source larger=No;conclusion=no_impossibility_certificate

Conditions: none

An injection has as many distinct images as source elements,all within the target,hence ns≤nt.A larger source contradicts this and excludes every injection.No means this size-based impossibility certificate does not apply,not that an unspecified map failed.

Step identifiers and dependencies

Rule: finite_pigeonhole_all_injections_not_one_map_failure · Uses: G001, S001

Reverse checks

  • 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

(2, 3, No, no_impossibility_certificate)

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: 005a1c6dc60e7efe5989a92853191d4a918c16f83c9a1eafa35f811981ecaef4
  • candidate record SHA-256: 0b67396255609cb0cf41024cf64599aa02b5a04e28c7a8cdf4694c33fdcb19db
  • semantic review receipt SHA-256: bfea39236e49aa7e44aa18bfa0d7857ff34a6acb762d0599e20b0f5af0f209ae
  • question-first witness SHA-256: 61c433f5c1e55ed4d84d08557fb8c117d26bbd404fdf05519ad42c09324c36e0
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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