# Question 1502: Every Fixed Point of the Given Finite Self-Map

[Return to catalogue page 8](https://ocme.evemisslab.com/en/questions/page/8/)

[← Question derivation index](https://ocme.evemisslab.com/en/questions/) · [Original question batch](https://ocme.evemisslab.com/en/practice/batch-20261013-advance-20261020-r01-discrete-dynamical-system-foundations/#q-20261013-advance-20261020-r01-discrete-dynamical-system-0052)

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.

R0002-01502 · q-20261013-advance-20261020-r01-discrete-dynamical-system-0052



## 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=-3, b=3. 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. Give (modulus, a, b, every x with T(x)=x in increasing order).


- G001 — Use the complete finite self-map on Fin(6)={0,…,5} given by T(x)=(a*x+b) mod 6, a=-3, b=3. 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. Give (modulus, a, b, every x with T(x)=x in increasing order).





## 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-discrete-dynamical-system](https://ocme.evemisslab.com/en/mko/mko-discrete-dynamical-system/)





## Step-by-step derivation

S001 · impliesBefore

X={0 through 5}; T(x)=(-3x+(3)) 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 dependenciesRule: finite_total_map · Uses: G001





S002 · calculationBefore

candidate0: a·x := mul(-3, 0)

After

candidate0: a·x = 0

Conditions: none

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

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S001





S003 · calculationBefore

candidate0: a·x+b := sum(0, 3)

After

candidate0: a·x+b = 3

Conditions: none

Add the same offset before reducing modulo n.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S002





S004 · impliesBefore

reduce 3 modulo 6

After

3=0·6+3

Conditions: none

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

Step identifiers and dependenciesRule: euclidean_remainder · Uses: G001, S003





S005 · impliesBefore

T(0)=3

After

fixed-point condition T(x)=x: No

Conditions: none

A fixed point must remain the same state after updating;merely remaining in the carrier is insufficient.

Step identifiers and dependenciesRule: fixed_point_equality · Uses: G001, S004





S006 · calculationBefore

candidate1: a·x := mul(-3, 1)

After

candidate1: a·x = -3

Conditions: none

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

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S005





S007 · calculationBefore

candidate1: a·x+b := sum(-3, 3)

After

candidate1: a·x+b = 0

Conditions: none

Add the same offset before reducing modulo n.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S006





S008 · impliesBefore

reduce 0 modulo 6

After

0=0·6+0

Conditions: none

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

Step identifiers and dependenciesRule: euclidean_remainder · Uses: G001, S007





S009 · impliesBefore

T(1)=0

After

fixed-point condition T(x)=x: No

Conditions: none

A fixed point must remain the same state after updating;merely remaining in the carrier is insufficient.

Step identifiers and dependenciesRule: fixed_point_equality · Uses: G001, S008





S010 · calculationBefore

candidate2: a·x := mul(-3, 2)

After

candidate2: a·x = -6

Conditions: none

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

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S009





S011 · calculationBefore

candidate2: a·x+b := sum(-6, 3)

After

candidate2: a·x+b = -3

Conditions: none

Add the same offset before reducing modulo n.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S010





S012 · impliesBefore

reduce -3 modulo 6

After

-3=-1·6+3

Conditions: none

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

Step identifiers and dependenciesRule: euclidean_remainder · Uses: G001, S011





S013 · impliesBefore

T(2)=3

After

fixed-point condition T(x)=x: No

Conditions: none

A fixed point must remain the same state after updating;merely remaining in the carrier is insufficient.

Step identifiers and dependenciesRule: fixed_point_equality · Uses: G001, S012





S014 · calculationBefore

candidate3: a·x := mul(-3, 3)

After

candidate3: a·x = -9

Conditions: none

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

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S013





S015 · calculationBefore

candidate3: a·x+b := sum(-9, 3)

After

candidate3: a·x+b = -6

Conditions: none

Add the same offset before reducing modulo n.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S014





S016 · impliesBefore

reduce -6 modulo 6

After

-6=-1·6+0

Conditions: none

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

Step identifiers and dependenciesRule: euclidean_remainder · Uses: G001, S015





S017 · impliesBefore

T(3)=0

After

fixed-point condition T(x)=x: No

Conditions: none

A fixed point must remain the same state after updating;merely remaining in the carrier is insufficient.

Step identifiers and dependenciesRule: fixed_point_equality · Uses: G001, S016





S018 · calculationBefore

candidate4: a·x := mul(-3, 4)

After

candidate4: a·x = -12

Conditions: none

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

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S017





S019 · calculationBefore

candidate4: a·x+b := sum(-12, 3)

After

candidate4: a·x+b = -9

Conditions: none

Add the same offset before reducing modulo n.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S018





S020 · impliesBefore

reduce -9 modulo 6

After

-9=-2·6+3

Conditions: none

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

Step identifiers and dependenciesRule: euclidean_remainder · Uses: G001, S019





S021 · impliesBefore

T(4)=3

After

fixed-point condition T(x)=x: No

Conditions: none

A fixed point must remain the same state after updating;merely remaining in the carrier is insufficient.

Step identifiers and dependenciesRule: fixed_point_equality · Uses: G001, S020





S022 · calculationBefore

candidate5: a·x := mul(-3, 5)

After

candidate5: a·x = -15

Conditions: none

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

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S021





S023 · calculationBefore

candidate5: a·x+b := sum(-15, 3)

After

candidate5: a·x+b = -12

Conditions: none

Add the same offset before reducing modulo n.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S022





S024 · impliesBefore

reduce -12 modulo 6

After

-12=-2·6+0

Conditions: none

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

Step identifiers and dependenciesRule: euclidean_remainder · Uses: G001, S023





S025 · impliesBefore

T(5)=0

After

fixed-point condition T(x)=x: No

Conditions: none

A fixed point must remain the same state after updating;merely remaining in the carrier is insufficient.

Step identifiers and dependenciesRule: fixed_point_equality · Uses: G001, S024





S026 · impliesBefore

all 6 carrier elements audited

After

complete fixed set=[]

Conditions: none

The full finite carrier was exhausted,so no fixed point is omitted;an empty list means this T has none.

Step identifiers and dependenciesRule: exhaustive_fixed_inventory · Uses: G001, S025









## Reverse checks


- S026 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
- S025 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
- S024 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
- S023 · premise_and_result_audit — Recompute candidate5: a·x+b with exact rational arithmetic, not rounded decimals.
- S022 · premise_and_result_audit — Recompute candidate5: a·x with exact rational arithmetic, not rounded decimals.
- S021 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
- S020 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
- S019 · premise_and_result_audit — Recompute candidate4: a·x+b with exact rational arithmetic, not rounded decimals.
- S018 · premise_and_result_audit — Recompute candidate4: a·x with exact rational arithmetic, not rounded decimals.
- S017 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
- S016 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
- S015 · premise_and_result_audit — Recompute candidate3: a·x+b with exact rational arithmetic, not rounded decimals.
- S014 · premise_and_result_audit — Recompute candidate3: a·x with exact rational arithmetic, not rounded decimals.
- S013 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
- S012 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
- S011 · premise_and_result_audit — Recompute candidate2: a·x+b with exact rational arithmetic, not rounded decimals.
- S010 · premise_and_result_audit — Recompute candidate2: a·x with exact rational arithmetic, not rounded decimals.
- 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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.
- S007 · premise_and_result_audit — Recompute candidate1: a·x+b with exact rational arithmetic, not rounded decimals.
- S006 · premise_and_result_audit — Recompute candidate1: a·x with exact rational arithmetic, not rounded decimals.
- 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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.
- S003 · premise_and_result_audit — Recompute candidate0: a·x+b with exact rational arithmetic, not rounded decimals.
- S002 · premise_and_result_audit — Recompute candidate0: a·x 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

(6, -3, 3, [])

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: 6718132450009ffda1f74a4bcd00d797bd5c6eff6f303100c2288e1ffa9f6180
- candidate record SHA-256: d4cfedea886ecc3c61f46858d951acf44ce7ddaf65c10f0cb5362532614df624
- semantic review receipt SHA-256: 340d74dcc6e37df6249594a0b79a9ee2af804337b7847478b3c1342af9722861
- question-first witness SHA-256: 9a06233d190d31a16f13fb03b6c3ceba4cbb748fff6c997941f66ab1888dcca8
- Lean: NOT_RUN · human review: NOT_PERFORMED

[Same-source full JSON](https://ocme.evemisslab.com/data/question-derivations/questions/q-20261013-advance-20261020-r01-discrete-dynamical-system-0052.json)




