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Question 14590: Use the Nonnegative Exact Root of the Same Self-Inner-Product

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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R0028-14590 · q-20261014-advance-20261029-r03-inner-product-induced-norm-0015

Original question and givens

Use the same certified real inner product on R², <u,v>=u^T A v, with A=[[16, 2], [2, 5]] and x=[-3, 2]. The complete integer matrix must be symmetric with a positive leading entry and positive determinant. The induced norm is the nonnegative sqrt(<x,x>), with exact sqrt(...) text retained without simplification. Cauchy–Schwarz is a universal mathematical certificate, not proved by these vector instances or a new Lean receipt. Completeness and Hilbert structure are not inferred. Give (matrix,x,norm_square,exact_norm,same_inner_product_universal_norm_certificate).

  • G001 — Use the same certified real inner product on R², <u,v>=u^T A v, with A=[[16, 2], [2, 5]] and x=[-3, 2]. The complete integer matrix must be symmetric with a positive leading entry and positive determinant. The induced norm is the nonnegative sqrt(<x,x>), with exact sqrt(...) text retained without simplification. Cauchy–Schwarz is a universal mathematical certificate, not proved by these vector instances or a new Lean receipt. Completeness and Hilbert structure are not inferred. Give (matrix,x,norm_square,exact_norm,same_inner_product_universal_norm_certificate).

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 · calculation

Before

inner parent diagonal product := mul(16, 5)

After

inner parent diagonal product = 80

Conditions: none

Compute exactly from original roles and established intermediates,retaining denominators,signs,indices and necessary guards.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001

S002 · calculation

Before

inner parent off-diagonal product := mul(2, 2)

After

inner parent off-diagonal product = 4

Conditions: none

Compute exactly from original roles and established intermediates,retaining denominators,signs,indices and necessary guards.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S001

S003 · calculation

Before

inner parent determinant := sub(80, 4)

After

inner parent determinant = 76

Conditions: none

Compute exactly from original roles and established intermediates,retaining denominators,signs,indices and necessary guards.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · implies

Before

same real R2 inner-product candidate matrix=[[16, 2], [2, 5]]

After

symmetric=Yes;leading=16;determinant=76

Conditions: none

Qualify the same symmetric positive-definite real R² parent matrix,not an unrelated Euclidean or coordinate norm.Symmetry,positive leading entry and positive determinant are required.

Step identifiers and dependencies

Rule: innernorm_certified_same_SPD_parent · Uses: G001, S003

S005 · calculation

Before

inner parent completed-square slope := div(2, 16)

After

inner parent completed-square slope = 1/8

Conditions: none

Compute exactly from original roles and established intermediates,retaining denominators,signs,indices and necessary guards.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

S006 · calculation

Before

inner parent completed-square remainder := div(76, 16)

After

inner parent completed-square remainder = 19/4

Conditions: none

Compute exactly from original roles and established intermediates,retaining denominators,signs,indices and necessary guards.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S005

S007 · implies

Before

positive leading=16;slope=1/8;positive remainder=19/4

After

q(s,t)=(16)*(s+(1/8)*t)^2+(19/4)*t^2;positive iff(s,t)!=0

Conditions: none

The two positive completed-square coefficients give positive self-inner-product for every nonzero real vector and0 at zero,not merely sampled positive values.

Step identifiers and dependencies

Rule: innernorm_parent_global_positive_square_certificate · Uses: G001, S006

S008 · implies

Before

same certified real inner product;arbitrary real x,y

After

if y=0 then inner(x,y)=0;otherwise yy>0 and q(x-a*y)=xx-2*a*xy+a^2*yy>=0

Conditions: none

For every real a,self-inner-product is nonnegative.When y≠0,yy>0;choose a=xy/yy to obtain xx−xy²/yy≥0,multiply by positive yy to get xy²≤xx*yy.Handle y=0 separately without0/0.

Step identifiers and dependencies

Rule: innernorm_Cauchy_Schwarz_all_vectors_quadratic · Uses: G001, S007

S009 · implies

Before

norm(x)=nonnegative sqrt(inner(x,x));inner product positive definite and bilinear

After

norm(x)>=0;norm(x)=0 iff x=0;norm(a*x)=abs(a)*norm(x)

Conditions: none

Only the nonnegative root is the norm.From q(ax)=a²q(x),taking roots gives|a|,not a,including negative scalars.The zero and homogeneity claims are universal.

Step identifiers and dependencies

Rule: innernorm_nonnegative_root_and_absolute_homogeneity · Uses: G001, S008

S010 · implies

Before

Cauchy-Schwarz holds for arbitrary x,y in this same inner product

After

norm(x+y)^2=xx+2*xy+yy<=(norm(x)+norm(y))^2;nonnegative roots give triangle inequality

Conditions: none

Bound the cross term by|xy|≤norm(x)norm(y),then take nonnegative roots for the universal triangle inequality.One exact instance is not the theorem's source,and no completeness follows.

Step identifiers and dependencies

Rule: innernorm_triangle_uses_universal_Cauchy_Schwarz · Uses: G001, S009

S011 · implies

Before

x self-inner-product:same matrix=[[16, 2], [2, 5]];first vector=[-3, 2];second vector=[-3, 2]

After

inner product=first^T*(matrix*second)

Conditions: none

Use the same parent inner product:matrix times second slot,then dot with first.Derived rational vectors still belong to R² and are not clipped to raw integer input bounds.

Step identifiers and dependencies

Rule: innernorm_original_slot_roles · Uses: G001, S010

S012 · calculation

Before

x self-inner-product matrix term0,0 := mul(16, -3)

After

x self-inner-product matrix term0,0 = -48

Conditions: none

Compute exactly from original roles and established intermediates,retaining denominators,signs,indices and necessary guards.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S011

S013 · calculation

Before

x self-inner-product matrix term0,1 := mul(2, 2)

After

x self-inner-product matrix term0,1 = 4

Conditions: none

Compute exactly from original roles and established intermediates,retaining denominators,signs,indices and necessary guards.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S012

S014 · calculation

Before

x self-inner-product image coordinate0 := sum(-48, 4)

After

x self-inner-product image coordinate0 = -44

Conditions: none

Compute exactly from original roles and established intermediates,retaining denominators,signs,indices and necessary guards.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S013

S015 · calculation

Before

x self-inner-product matrix term1,0 := mul(2, -3)

After

x self-inner-product matrix term1,0 = -6

Conditions: none

Compute exactly from original roles and established intermediates,retaining denominators,signs,indices and necessary guards.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S014

S016 · calculation

Before

x self-inner-product matrix term1,1 := mul(5, 2)

After

x self-inner-product matrix term1,1 = 10

Conditions: none

Compute exactly from original roles and established intermediates,retaining denominators,signs,indices and necessary guards.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S015

S017 · calculation

Before

x self-inner-product image coordinate1 := sum(-6, 10)

After

x self-inner-product image coordinate1 = 4

Conditions: none

Compute exactly from original roles and established intermediates,retaining denominators,signs,indices and necessary guards.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S016

S018 · calculation

Before

x self-inner-product first-slot term0 := mul(-3, -44)

After

x self-inner-product first-slot term0 = 132

Conditions: none

Compute exactly from original roles and established intermediates,retaining denominators,signs,indices and necessary guards.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S017

S019 · calculation

Before

x self-inner-product first-slot term1 := mul(2, 4)

After

x self-inner-product first-slot term1 = 8

Conditions: none

Compute exactly from original roles and established intermediates,retaining denominators,signs,indices and necessary guards.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S018

S020 · calculation

Before

x self-inner-product inner sum := sum(132, 8)

After

x self-inner-product inner sum = 140

Conditions: none

Compute exactly from original roles and established intermediates,retaining denominators,signs,indices and necessary guards.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S019

S021 · implies

Before

induced norm:same-form self-inner-product=140>=0

After

nonnegative exact root=sqrt(140);source expression kept unsimplified

Conditions: none

Retain the exact source sqrt(...) string even for a perfect square,without integer/decimal replacement.The negative root is not a norm/distance,and no other inner product or norm is substituted.

Step identifiers and dependencies

Rule: innernorm_exact_root_not_decimal_or_other_metric · Uses: G001, S020

Reverse checks

  • 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 — Recompute x self-inner-product inner sum with exact rational arithmetic, not rounded decimals.
  • S019 · premise_and_result_audit — Recompute x self-inner-product first-slot term1 with exact rational arithmetic, not rounded decimals.
  • S018 · premise_and_result_audit — Recompute x self-inner-product first-slot term0 with exact rational arithmetic, not rounded decimals.
  • S017 · premise_and_result_audit — Recompute x self-inner-product image coordinate1 with exact rational arithmetic, not rounded decimals.
  • S016 · premise_and_result_audit — Recompute x self-inner-product matrix term1,1 with exact rational arithmetic, not rounded decimals.
  • S015 · premise_and_result_audit — Recompute x self-inner-product matrix term1,0 with exact rational arithmetic, not rounded decimals.
  • S014 · premise_and_result_audit — Recompute x self-inner-product image coordinate0 with exact rational arithmetic, not rounded decimals.
  • S013 · premise_and_result_audit — Recompute x self-inner-product matrix term0,1 with exact rational arithmetic, not rounded decimals.
  • S012 · premise_and_result_audit — Recompute x self-inner-product matrix term0,0 with exact rational arithmetic, not rounded decimals.
  • S011 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • 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 — Recompute inner parent completed-square remainder with exact rational arithmetic, not rounded decimals.
  • S005 · premise_and_result_audit — Recompute inner parent completed-square slope with exact rational arithmetic, not rounded decimals.
  • 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 inner parent determinant with exact rational arithmetic, not rounded decimals.
  • S002 · premise_and_result_audit — Recompute inner parent off-diagonal product with exact rational arithmetic, not rounded decimals.
  • S001 · premise_and_result_audit — Recompute inner parent diagonal product with exact rational arithmetic, not rounded decimals.

Result

([[16, 2], [2, 5]], [-3, 2], 140, sqrt(140), same_inner_product_universal_norm_certificate)

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: 7a7bcbe5e03ebe8c23934e02057837ccb9b965f20df9fca3553a5637eff3c1ff
  • candidate record SHA-256: e19cb29ad8f296980251a6329787e7a50b8143438dbd6dafe7a47836302f9564
  • semantic review receipt SHA-256: bfea39236e49aa7e44aa18bfa0d7857ff34a6acb762d0599e20b0f5af0f209ae
  • question-first witness SHA-256: 61c433f5c1e55ed4d84d08557fb8c117d26bbd404fdf05519ad42c09324c36e0
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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