Question 6728: Reported Factorials versus Exact Values and Recurrence

Original question and givens

N begins at 0, F(0)=0!=1, and factorials use exact integer arithmetic, not floating point. n=2; candidate decimal integer strings u=2, v=7. Give (actual F(n), actual F(n+1), u−F(n), v−(n+1)u, are both reports correct?).

• G001 — N begins at 0, F(0)=0!=1, and factorials use exact integer arithmetic, not floating point. n=2; candidate decimal integer strings u=2, v=7. Give (actual F(n), actual F(n+1), u−F(n), v−(n+1)u, are both reports correct?).

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-factorial

Step-by-step derivation

N includes0;F(0)=1;F(j)=j·F(j−1)

exact integer products,not floating values or a permutation proof

actual factorial:start at F(0)

F(0)=1

actual factorial through factor1 := mul(1, 1)

actual factorial through factor1 = 1

actual factorial through factor2 := mul(1, 2)

actual factorial through factor2 = 2

true successor factorial := mul(3, 2)

true successor factorial = 6

reported u minus true factorial := sub(2, 2)

reported u minus true factorial = 0

successor predicted from reported u := mul(3, 2)

successor predicted from reported u = 6

reported successor recurrence defect := sub(7, 6)

reported successor recurrence defect = 1

true values=(2,6);reports=(2,7);defects=(0,1)

both reports true=No

Reverse checks

• S009 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
• S008 · premise_and_result_audit — Recompute reported successor recurrence defect with exact rational arithmetic, not rounded decimals.
• S007 · premise_and_result_audit — Recompute successor predicted from reported u with exact rational arithmetic, not rounded decimals.
• S006 · premise_and_result_audit — Recompute reported u minus true factorial with exact rational arithmetic, not rounded decimals.
• S005 · premise_and_result_audit — Recompute true successor factorial with exact rational arithmetic, not rounded decimals.
• S004 · premise_and_result_audit — Recompute actual factorial through factor2 with exact rational arithmetic, not rounded decimals.
• S003 · premise_and_result_audit — Recompute actual factorial through factor1 with exact rational arithmetic, not rounded decimals.
• 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, 6, 0, 1, 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.