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Question 14754: Finite Convolution May Lose Degree over a Ring with Zero Divisors

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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R0028-14754 · q-20261014-advance-20261029-r02-polynomial-ring-over-finite-commutative-ring-0054

Original question and givens

Use the same qualified complete finite commutative unital ring on Fin(4)={0,…,3}, with addition=[[0, 1, 2, 3], [1, 3, 0, 2], [2, 0, 3, 1], [3, 2, 1, 0]] and multiplication=[[0, 0, 0, 0], [0, 2, 1, 3], [0, 1, 2, 3], [0, 3, 3, 0]] in carrier-label order. All ring axioms and distinct two-sided identities already hold; the zero and one labels need not be 0 and 1. No nonzero-zero-divisor or field premise is silently added. Polynomial coefficients are in increasing exponent order and have finite support. Remove trailing copies of the actual ring zero, representing the zero polynomial by [zero]. The output field degree is the last index of that normalized array, hence 0 for [zero] in this protocol; it is not a claim about the usual degree convention for the zero polynomial. A finite coefficient ring does not make ordinary R[x] finite, and zero divisors forbid an unconditional degree-of-product equality. left=[0, 3, 0, 0], right=[2, 0, 0, 0]. Give (normalized_left,normalized_right,product,degree,degree_additivity_not_claimed_with_zero_divisors).

  • G001 — Use the same qualified complete finite commutative unital ring on Fin(4)={0,…,3}, with addition=[[0, 1, 2, 3], [1, 3, 0, 2], [2, 0, 3, 1], [3, 2, 1, 0]] and multiplication=[[0, 0, 0, 0], [0, 2, 1, 3], [0, 1, 2, 3], [0, 3, 3, 0]] in carrier-label order. All ring axioms and distinct two-sided identities already hold; the zero and one labels need not be 0 and 1. No nonzero-zero-divisor or field premise is silently added. Polynomial coefficients are in increasing exponent order and have finite support. Remove trailing copies of the actual ring zero, representing the zero polynomial by [zero]. The output field degree is the last index of that normalized array, hence 0 for [zero] in this protocol; it is not a claim about the usual degree convention for the zero polynomial. A finite coefficient ring does not make ordinary R[x] finite, and zero divisors forbid an unconditional degree-of-product equality. left=[0, 3, 0, 0], right=[2, 0, 0, 0]. Give (normalized_left,normalized_right,product,degree,degree_additivity_not_claimed_with_zero_divisors).

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

same carrier Fin(4);addition=[[0, 1, 2, 3], [1, 3, 0, 2], [2, 0, 3, 1], [3, 2, 1, 0]];multiplication=[[0, 0, 0, 0], [0, 2, 1, 3], [0, 1, 2, 3], [0, 3, 3, 0]]

After

actual additive zero=0;actual multiplicative one=2;additive inverses=[0, 2, 1, 3]

Conditions: none

Bind coefficients and domain reasoning to the same complete parent tables.Identities are actual elements,not presumed labels0 or1.

Step identifiers and dependencies

Rule: commutative_parent_actual_tables_and_identities · Uses: G001

S002 · implies

Before

all additive/multiplicative pairs and triples checked;first failures=[null, null, null, null]

After

additive commute=Yes;multiplicative commute=Yes;zero differs from one=Yes

Conditions: none

Qualify the whole additive abelian group,multiplicative associativity/commutativity,both distributive laws and distinct identities.Domain and polynomial obligations follow this premise,not sampled successes.

Step identifiers and dependencies

Rule: complete_commutative_unital_parent_qualification · Uses: G001, S001

S003 · implies

Before

left polynomial:raw ascending coefficient labels=[0, 3, 0, 0];actual ring zero=0

After

normalized finite support=[0, 3];last-index degree field=1

Conditions: none

Remove only trailing actual-zero coefficients,not low-degree or internal zeros.Empty/all-zero inputs become[zero].Here degree means last index and returns0 for the zero polynomial,not the usual mathematical zero-polynomial degree convention.

Step identifiers and dependencies

Rule: polynomial_trailing_actual_zero_protocol · Uses: G001, S002

S004 · implies

Before

right polynomial:raw ascending coefficient labels=[2, 0, 0, 0];actual ring zero=0

After

normalized finite support=[2];last-index degree field=0

Conditions: none

Remove only trailing actual-zero coefficients,not low-degree or internal zeros.Empty/all-zero inputs become[zero].Here degree means last index and returns0 for the zero polynomial,not the usual mathematical zero-polynomial degree convention.

Step identifiers and dependencies

Rule: polynomial_trailing_actual_zero_protocol · Uses: G001, S003

S005 · implies

Before

convolution coefficient0 times coefficient0:operation=multiplication;left label=0;right label=2;original row=[0, 0, 0, 0]

After

result label=0

Conditions: none

Use the original operation/order lookup.Labels are not integer sums/products,and modular guesses do not define the parent ring.

Step identifiers and dependencies

Rule: same_parent_operation_not_integer_labels · Uses: G001, S004

S006 · implies

Before

accumulate product at degree0:operation=addition;left label=0;right label=0;original row=[0, 1, 2, 3]

After

result label=0

Conditions: none

Use the original operation/order lookup.Labels are not integer sums/products,and modular guesses do not define the parent ring.

Step identifiers and dependencies

Rule: same_parent_operation_not_integer_labels · Uses: G001, S005

S007 · implies

Before

convolution coefficient1 times coefficient0:operation=multiplication;left label=3;right label=2;original row=[0, 3, 3, 0]

After

result label=3

Conditions: none

Use the original operation/order lookup.Labels are not integer sums/products,and modular guesses do not define the parent ring.

Step identifiers and dependencies

Rule: same_parent_operation_not_integer_labels · Uses: G001, S006

S008 · implies

Before

accumulate product at degree1:operation=addition;left label=0;right label=3;original row=[0, 1, 2, 3]

After

result label=3

Conditions: none

Use the original operation/order lookup.Labels are not integer sums/products,and modular guesses do not define the parent ring.

Step identifiers and dependencies

Rule: same_parent_operation_not_integer_labels · Uses: G001, S007

S009 · implies

Before

product result:raw ascending coefficient labels=[0, 3];actual ring zero=0

After

normalized finite support=[0, 3];last-index degree field=1

Conditions: none

Remove only trailing actual-zero coefficients,not low-degree or internal zeros.Empty/all-zero inputs become[zero].Here degree means last index and returns0 for the zero polynomial,not the usual mathematical zero-polynomial degree convention.

Step identifiers and dependencies

Rule: polynomial_trailing_actual_zero_protocol · Uses: G001, S008

S010 · implies

Before

normalized product=[0, 3];last-index degree field=1

After

degree_additivity_not_claimed_with_zero_divisors

Conditions: none

Convolve finite supports using parent-ring operations,then trim trailing zeros.Leading coefficients may annihilate through zero divisors,and two nonzero polynomials may multiply to zero.No unconditional degree-additivity or field property is claimed.

Step identifiers and dependencies

Rule: polynomial_convolution_zero_divisor_boundary · Uses: G001, S009

Reverse checks

  • S010 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • 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 — 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 — 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 — 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

([0, 3], [2], [0, 3], 1, degree_additivity_not_claimed_with_zero_divisors)

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: c0d27e67d261678811d4c33d7fcda9f237a2d744accfb6d22b0b8117bdcfbdf1
  • candidate record SHA-256: 0ef107eac33cc7e390ef7b4adbebaa84cb8626fc8c1778f85a6e7def60d5d64b
  • semantic review receipt SHA-256: bfea39236e49aa7e44aa18bfa0d7857ff34a6acb762d0599e20b0f5af0f209ae
  • question-first witness SHA-256: 61c433f5c1e55ed4d84d08557fb8c117d26bbd404fdf05519ad42c09324c36e0
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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