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Question 1552: A Fixed-Length Discrete Orbit Prefix

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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R0002-01552 · q-20261013-advance-20261020-r01-discrete-dynamical-system-0027

Original question and givens

Use the complete finite self-map on Fin(6)={0,…,5} given by T(x)=(a*x+b) mod 6, a=2, b=-4. Choose the least nonnegative residue, including for negative a*x+b. Time is discrete, indexed from 0; a finite orbit is not a general stability result. x0=1, updates=1. Give (modulus, a, b, x0, update count, orbit including x0). Zero updates gives the one-element prefix [x0].

  • G001 — Use the complete finite self-map on Fin(6)={0,…,5} given by T(x)=(a*x+b) mod 6, a=2, b=-4. Choose the least nonnegative residue, including for negative a*x+b. Time is discrete, indexed from 0; a finite orbit is not a general stability result. x0=1, updates=1. Give (modulus, a, b, x0, update count, orbit including x0). Zero updates gives the one-element prefix [x0].

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

X={0 through 5}; T(x)=(2x+(-4)) mod 6

After

remainder representative always lies in X

Conditions: none

Fix the full finite state carrier and the same update rule;negative integers also use the standard remainder from0 through n−1.

Step identifiers and dependencies

Rule: finite_total_map · Uses: G001

S002 · implies

Before

x₀=1; transitions=1

After

initial orbit prefix=[1]

Conditions: none

Retain the initial state;steps=0 still has one known state,not an empty list.

Step identifiers and dependencies

Rule: orbit_initial_state · Uses: G001, S001

S003 · calculation

Before

transition1: a·x := mul(2, 1)

After

transition1: a·x = 2

Conditions: none

Multiply the original coefficient by the current state;do not clip negative values to0.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · calculation

Before

transition1: a·x+b := sum(2, -4)

After

transition1: a·x+b = -2

Conditions: none

Add the same offset before reducing modulo n.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · implies

Before

reduce -2 modulo 6

After

-2=-1·6+4

Conditions: none

The integer identity together with0≤remainder<n determines the next state.

Step identifiers and dependencies

Rule: euclidean_remainder · Uses: G001, S004

S006 · implies

Before

computed transitions=1

After

orbit=[1, 4]; number of entries=2

Conditions: none

Apply the same T to the preceding result; k transitions give k+1 states.

Step identifiers and dependencies

Rule: orbit_prefix_length · Uses: G001, S005

S007 · implies

Before

a finite requested prefix

After

no unrequested least-period claim

Conditions: none

This output is the requested prefix;it is not an unverified least-period proof from a few orbit values.

Step identifiers and dependencies

Rule: finite_prefix_scope · Uses: G001, S006

Reverse checks

  • S007 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S006 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S005 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S004 · premise_and_result_audit — Recompute transition1: a·x+b with exact rational arithmetic, not rounded decimals.
  • S003 · premise_and_result_audit — Recompute transition1: a·x 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

(6, 2, -4, 1, 1, [1, 4])

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: a37a55d91f3aca3be4686ab86e18dc5a4d838c5b622d73224e527d28138f3656
  • candidate record SHA-256: 454725dad84a041781465c40ed0a1c974f364934c69ef38a7425e227c87c8f28
  • semantic review receipt SHA-256: 340d74dcc6e37df6249594a0b79a9ee2af804337b7847478b3c1342af9722861
  • question-first witness SHA-256: 9a06233d190d31a16f13fb03b6c3ceba4cbb748fff6c997941f66ab1888dcca8
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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