# Question 27776: All Nonzero Prime Residues Pair with Inverses, with a Special p=2 Case [Return to catalogue page 139](https://ocme.evemisslab.com/en/questions/page/139/) [← Question derivation index](https://ocme.evemisslab.com/en/questions/) · [Original question batch](https://ocme.evemisslab.com/en/practice/batch-20261015-advance-20261118-r04-wilson-theorem-foundations/#q-20261015-advance-20261118-r04-wilson-theorem-0026) This teaching derivation has second-context AI mathematical and bilingual semantic review, limited to the model and assumptions stated in this question. It has no human review or new Lean proof and does not promote the original question or MKO to Canonical truth. R0054-27776 · q-20261015-advance-20261118-r04-wilson-theorem-0026 ## Original question and givens Use prime modulus p=2. Give (p, all_inverse_pairs, self_inverse_residues, distinct_cancelling_pairs, self_inverse_scope, factorial_residue, Wilson_congruence). - G001 — Use prime modulus p=2. Give (p, all_inverse_pairs, self_inverse_residues, distinct_cancelling_pairs, self_inverse_scope, factorial_residue, Wilson_congruence). ## 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-wilson-theorem](https://ocme.evemisslab.com/en/mko/mko-wilson-theorem/) ## Step-by-step derivation S001 · impliesBefore source roles = [wilson-prime-inverse-pairing] After derived = [[p, all_inverse_pairs, self_inverse_residues, distinct_cancelling_pairs, self_inverse_scope, factorial_residue, Wilson_congruence]] Conditions: none List the complete operation/mode field order without JavaScript or answer-shape inference;Boolean,string,null and an unclaimed result remain distinct. Step identifiers and dependenciesRule: source_ordered_fields_without_JS · Uses: G001 S002 · impliesBefore source roles = [2, 1] After derived = [1, 1] Conditions: none Every nonzero residue at a prime modulus is a unit.For each a find the first source inverse;two inverses coincide by cancellation of a. Step identifiers and dependenciesRule: Wilson_EVERY_nonzero_prime_residue_unique_inverse · Uses: G001, S001 S003 · calculationBefore Wilson ORIGINAL prime factorial ORIGINAL running factorial product1 := mul(1, 1) After Wilson ORIGINAL prime factorial ORIGINAL running factorial product1 = 1 Conditions: none Substitute original roles and established intermediates exactly,not approximations or internally consistent changed operands;extra teaching algebra adds no source-domain gate. Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S002 S004 · impliesBefore source roles = [Wilson ORIGINAL prime factorial, 2, 1, 1, 1] After derived = [0, 1, Yes, Yes] Conditions: none Retain the prior residue and full product at every k,then its unique Euclidean remainder in0..n-1.The invariant is value congruent to k! mod n,not an assumed last table entry. Step identifiers and dependenciesRule: Wilson_EACH_running_factorial_exact_Euclidean_remainder · Uses: G001, S003 S005 · impliesBefore source roles = [2, [[1, 1]]] After derived = [[1], [], 1, Yes] Conditions: none Nonself inverse pairs multiply to1.A self-inverse satisfies(r-1)(r+1)=0 modulo a prime,so is±1.For p>2 their product is-1;at p2 only the single1=-1 remains.This general teaching argument does not turn the finite table/program into a Lean proof. Step identifiers and dependenciesRule: Wilson_GENERAL_inverse_pairing_and_p2_exception · Uses: G001, S004 ## Reverse checks - S005 · premise_and_result_audit — Reverse-check original data,operands,complete scope and premises;finite witnesses,conditional theorem use and formal proof remain distinct. - S004 · premise_and_result_audit — Reverse-check original data,operands,complete scope and premises;finite witnesses,conditional theorem use and formal proof remain distinct. - S003 · premise_and_result_audit — Recompute Wilson ORIGINAL prime factorial ORIGINAL running factorial product1 with exact rational arithmetic, not rounded decimals. - S002 · premise_and_result_audit — Reverse-check original data,operands,complete scope and premises;finite witnesses,conditional theorem use and formal proof remain distinct. - S001 · premise_and_result_audit — Reverse-check original data,operands,complete scope and premises;finite witnesses,conditional theorem use and formal proof remain distinct. ## Result (2, [[1, 1]], [1], [], single_self_inverse_residue_1_equals_minus_1, 1, Yes) 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: 7061a0dccc760991e807b903294efd4126de3ec4c57376e7c323728f9d0a3083 - candidate record SHA-256: bf29578f95fad051e2501194b2006f1f706243fe24f0927ed01961a68ad3e456 - semantic review receipt SHA-256: 0a76d8e93c08bb16998a0483f3dfc0504f269fc3e1982e6cd868cab0a2856d54 - question-first witness SHA-256: 09127b736c225714dfa0b7ceb0e6a6e66df27438b480cad8217d3c2f99ce9437 - Lean: NOT_RUN · human review: NOT_PERFORMED [Same-source full JSON](https://ocme.evemisslab.com/data/question-derivations/questions/q-20261015-advance-20261118-r04-wilson-theorem-0026.json)