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R0026-13995 · q-20261014-advance-20261028-r05-bounded-linear-operator-0045
Use the explicit rectangular integer matrix A=[[7, 2, -3], [2, -7, -2]] as a linear map between its column- and row-coordinate real spaces. Both ends use the same stated l1 or linfinity norm. A single C≥0 must bound every input: norm(A*x)≤C*norm(x). The exact l1 induced norm is the maximum absolute column sum; the exact linfinity induced norm is the maximum absolute row sum. An instance pass or a nonoptimal usable bound is not the exact operator norm. Give (matrix,row_sums,operator_norm,maximum_absolute_row_sum), preserving original row order.
G001 — Use the explicit rectangular integer matrix A=[[7, 2, -3], [2, -7, -2]] as a linear map between its column- and row-coordinate real spaces. Both ends use the same stated l1 or linfinity norm. A single C≥0 must bound every input: norm(A*x)≤C*norm(x). The exact l1 induced norm is the maximum absolute column sum; the exact linfinity induced norm is the maximum absolute row sum. An instance pass or a nonoptimal usable bound is not the exact operator norm. Give (matrix,row_sums,operator_norm,maximum_absolute_row_sum), preserving original row order.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.
Before
original row index=0;ordered entries=[7, 2, -3]
After
absolute entries=[7, 2, 3]
Conditions: none
For l1 sum down each column;for linfinity sum across each row.Preserve axis order and do not transpose rectangular roles.
Rule: operator_correct_axis_absolute_sum · Uses: G001
Before
operator row0 absolute sum := sum(7, 2, 3)
After
operator row0 absolute sum = 12
Conditions: none
Compute exactly from original roles and established intermediates,retaining coordinates,coefficients,signs and necessary guards.
Rule: exact_rational_arithmetic · Uses: G001, S001
Before
original row index=1;ordered entries=[2, -7, -2]
After
absolute entries=[2, 7, 2]
Conditions: none
For l1 sum down each column;for linfinity sum across each row.Preserve axis order and do not transpose rectangular roles.
Rule: operator_correct_axis_absolute_sum · Uses: G001, S002
Before
operator row1 absolute sum := sum(2, 7, 2)
After
operator row1 absolute sum = 11
Conditions: none
Compute exactly from original roles and established intermediates,retaining coordinates,coefficients,signs and necessary guards.
Rule: exact_rational_arithmetic · Uses: G001, S003
Before
all absolute row sums=[12, 11]
After
maximum=12;first maximizing row=0
Conditions: none
Compute every required axis sum before taking a maximum.The value must have both a universal upper bound and an attaining unit input.
Rule: operator_maximum_axis_sum · Uses: G001, S004
Before
arbitrary x in R^3;all row sums<=12
After
each abs((Ax)i)<=sum_j abs(Aij)*normInfinity(x)<=12*normInfinity(x);take maximum_i
Conditions: none
Each input coordinate is bounded by its maximum norm.Bound each row and then maximize over outputs to obtain a universal uniform bound.
Rule: operator_linfinity_universal_row_bound · Uses: G001, S005
Before
attaining unit input image:matrix=[[7, 2, -3], [2, -7, -2]];input=[1, 1, -1]
After
input dimension=3;output dimension=2;rows dot input
Conditions: none
Retain column-input/row-output roles for rectangular matrices.Computed values can exceed raw input bounds and are not clipped.
Rule: matrix_row_column_roles · Uses: G001, S006
Before
attaining unit input image row0 column0 product := mul(7, 1)
After
attaining unit input image row0 column0 product = 7
Conditions: none
Compute exactly from original roles and established intermediates,retaining coordinates,coefficients,signs and necessary guards.
Rule: exact_rational_arithmetic · Uses: G001, S007
Before
attaining unit input image row0 column1 product := mul(2, 1)
After
attaining unit input image row0 column1 product = 2
Conditions: none
Compute exactly from original roles and established intermediates,retaining coordinates,coefficients,signs and necessary guards.
Rule: exact_rational_arithmetic · Uses: G001, S008
Before
attaining unit input image row0 column2 product := mul(-3, -1)
After
attaining unit input image row0 column2 product = 3
Conditions: none
Compute exactly from original roles and established intermediates,retaining coordinates,coefficients,signs and necessary guards.
Rule: exact_rational_arithmetic · Uses: G001, S009
Before
attaining unit input image row0 sum := sum(7, 2, 3)
After
attaining unit input image row0 sum = 12
Conditions: none
Compute exactly from original roles and established intermediates,retaining coordinates,coefficients,signs and necessary guards.
Rule: exact_rational_arithmetic · Uses: G001, S010
Before
attaining unit input image row1 column0 product := mul(2, 1)
After
attaining unit input image row1 column0 product = 2
Conditions: none
Compute exactly from original roles and established intermediates,retaining coordinates,coefficients,signs and necessary guards.
Rule: exact_rational_arithmetic · Uses: G001, S011
Before
attaining unit input image row1 column1 product := mul(-7, 1)
After
attaining unit input image row1 column1 product = -7
Conditions: none
Compute exactly from original roles and established intermediates,retaining coordinates,coefficients,signs and necessary guards.
Rule: exact_rational_arithmetic · Uses: G001, S012
Before
attaining unit input image row1 column2 product := mul(-2, -1)
After
attaining unit input image row1 column2 product = 2
Conditions: none
Compute exactly from original roles and established intermediates,retaining coordinates,coefficients,signs and necessary guards.
Rule: exact_rational_arithmetic · Uses: G001, S013
Before
attaining unit input image row1 sum := sum(2, -7, 2)
After
attaining unit input image row1 sum = -3
Conditions: none
Compute exactly from original roles and established intermediates,retaining coordinates,coefficients,signs and necessary guards.
Rule: exact_rational_arithmetic · Uses: G001, S014
Before
attaining input:signed vector=[1, 1, -1];norm=linfinity
After
coordinate absolute values=[1, 1, 1]
Conditions: none
Take absolute values of whole coordinates without changing their pairing.This also accepts computed matrix images without clipping to raw input bounds.
Rule: operator_named_norm_original_signs · Uses: G001, S015
Before
attaining input:all absolute coordinates=[1, 1, 1]
After
maximum=1;first attaining coordinate=0
Conditions: none
The finite nonempty maximum must bound every value and be attained,not be the largest signed coordinate.
Rule: operator_linfinity_full_maximum · Uses: G001, S016
Before
attaining output:signed vector=[12, -3];norm=linfinity
After
coordinate absolute values=[12, 3]
Conditions: none
Take absolute values of whole coordinates without changing their pairing.This also accepts computed matrix images without clipping to raw input bounds.
Rule: operator_named_norm_original_signs · Uses: G001, S017
Before
attaining output:all absolute coordinates=[12, 3]
After
maximum=12;first attaining coordinate=0
Conditions: none
The finite nonempty maximum must bound every value and be attained,not be the largest signed coordinate.
Rule: operator_linfinity_full_maximum · Uses: G001, S018
Before
explicit input=[1, 1, -1];input norm=1;image=[12, -3];output norm=12
After
uniform upper bound=12 and attained ratio=12;exact induced norm=12
Conditions: none
For l1 take the maximizing column's basis vector;for linfinity take signs of a maximizing row.For a zero matrix still choose a nonzero unit vector.The universal bound L and an attained unit ratio L exclude every smaller constant,establishing the exact norm.
Rule: operator_attainment_proves_least_uniform_constant · Uses: G001, S019
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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.S018 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.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 attaining unit input image row1 sum with exact rational arithmetic, not rounded decimals.S014 · premise_and_result_audit — Recompute attaining unit input image row1 column2 product with exact rational arithmetic, not rounded decimals.S013 · premise_and_result_audit — Recompute attaining unit input image row1 column1 product with exact rational arithmetic, not rounded decimals.S012 · premise_and_result_audit — Recompute attaining unit input image row1 column0 product with exact rational arithmetic, not rounded decimals.S011 · premise_and_result_audit — Recompute attaining unit input image row0 sum with exact rational arithmetic, not rounded decimals.S010 · premise_and_result_audit — Recompute attaining unit input image row0 column2 product with exact rational arithmetic, not rounded decimals.S009 · premise_and_result_audit — Recompute attaining unit input image row0 column1 product with exact rational arithmetic, not rounded decimals.S008 · premise_and_result_audit — Recompute attaining unit input image row0 column0 product with exact rational arithmetic, not rounded decimals.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 operator row1 absolute sum with exact rational arithmetic, not rounded decimals.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 — Recompute operator row0 absolute sum 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.([[7, 2, -3], [2, -7, -2]], [12, 11], 12, maximum_absolute_row_sum)
The full substitutions and premise checks give the original answer; source identity,format and status are unchanged.
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.
input commit: 0f7be61e2c22317a4075561dc822c87d881a50dboriginal question SHA-256: d8557e9580aea6b48e2bd2ab39b781955ec79c227a6652753b8e890ecc1b04d7candidate record SHA-256: a4175be82cffe84a76144d701d8c92ec9fbf806813e376adc268d0099782a8ecsemantic review receipt SHA-256: f335caca08574c9f949c141083c66655fee51c227d45d80a3ddb7d78f862d798question-first witness SHA-256: cc7ba54738af91a6871fc1c20e45ad8f2b434392273fa334bd16a3b2238f4a77Lean: NOT_RUN · human review: NOT_PERFORMED