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Question 6926: Fraction Product and Two Reciprocal Guards

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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R0012-06926 · q-20261011-advance-20261015-r01-fraction-0051

Original question and givens

Use legal integer fraction representations with nonzero original denominators; negative denominators are allowed. Representation and value remain distinct. a=0/-2, b=0/3. Give (product, nonzero eligibility list for a and b separately, their reciprocals or undefined, reciprocal product or undefined).

  • G001 — Use legal integer fraction representations with nonzero original denominators; negative denominators are allowed. Representation and value remain distinct. a=0/-2, b=0/3. Give (product, nonzero eligibility list for a and b separately, their reciprocals or undefined, reciprocal product or undefined).

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

original integer numerator/denominator representations;original denominators nonzero

After

representation and rational value are distinct data

Conditions: none

Negative denominators are valid,but reduced values do not replace original representations.Candidate algorithms about raw numerators/denominators must use those raw data.This finite audit is not a general proof of quotient well-definedness.

Step identifiers and dependencies

Rule: fraction_representation_value_scope · Uses: G001

S002 · calculation

Before

fraction product := mul(0, 0)

After

fraction product = 0

Conditions: none

Multiply the values of the two valid fractions;zero values may still be multiplied.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S001

S003 · implies

Before

value=0/1;nonzero=No

After

reciprocal=undefined

Conditions: none

Test whether the value is0,not the sign of the original denominator.A zero numerator over a negative nonzero denominator is valid zero,but has no reciprocal.

Step identifiers and dependencies

Rule: fraction_reciprocal_value_guard · Uses: G001, S002

S004 · implies

Before

value=0/1;nonzero=No

After

reciprocal=undefined

Conditions: none

Test whether the value is0,not the sign of the original denominator.A zero numerator over a negative nonzero denominator is valid zero,but has no reciprocal.

Step identifiers and dependencies

Rule: fraction_reciprocal_value_guard · Uses: G001, S003

Reverse checks

  • 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 — Recompute fraction product with exact rational arithmetic, not rounded decimals.
  • S001 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.

Result

(0/1, [No, No], [undefined, undefined], undefined)

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: 2104d56cb03afd2998fbe31e31c357836de2849e6edafd65bf720df39b20006f
  • candidate record SHA-256: 55e0cbb2b0a36bb16910ef5b171d2cc0427b5b42c7cb6a991058cddf04534bfe
  • semantic review receipt SHA-256: 90dbc494b2d34ef51f412dcff63cfcc1a2215d038bff71f38f5dded4c64faf00
  • question-first witness SHA-256: b72a3b8bcf10f584396e0dd5198c657b0934a71864e5a3fa6321d7a613aef9f9
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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