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Question 13137: Distinguish a Universal Norm Certificate from Finite Samples

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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R0025-13137 · q-20261014-advance-20261027-r02-norm-induced-metric-0087

Original question and givens

Use one named, certified norm on a fixed real coordinate space: l1(v)=sum_i |v_i| or linfinity(v)=max_i |v_i|. Set d(x,y)=norm(x−y) on that same space. Its universal norm-axiom certificate establishes the metric axioms; finite distance samples do not. Do not infer that every metric comes from a norm, or claim completeness, compactness or an inner product. norm_name=linfinity, dimension=12, evidence_mode=named_formula_certificate. Give (norm_name,dimension,evidence_mode,sufficient?,boundary). named_formula_certificate yields universal_from_norm_axioms; finite_samples yields samples_do_not_establish_induced_metric.

  • G001 — Use one named, certified norm on a fixed real coordinate space: l1(v)=sum_i |v_i| or linfinity(v)=max_i |v_i|. Set d(x,y)=norm(x−y) on that same space. Its universal norm-axiom certificate establishes the metric axioms; finite distance samples do not. Do not infer that every metric comes from a norm, or claim completeness, compactness or an inner product. norm_name=linfinity, dimension=12, evidence_mode=named_formula_certificate. Give (norm_name,dimension,evidence_mode,sufficient?,boundary). named_formula_certificate yields universal_from_norm_axioms; finite_samples yields samples_do_not_establish_induced_metric.

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

certified named norm=linfinity;fixed real space R^12;d(x,y)=norm(x-y)

After

d>=0;d(x,y)=0 iff x-y=0 iff x=y

Conditions: none

The certified l1 or linfinity norm axioms give nonnegativity and separation at the zero vector.Substitute x−y to obtain metric separation.

Step identifiers and dependencies

Rule: norm_metric_positivity_and_separation · Uses: G001

S002 · implies

Before

arbitrary x,y in R^12;y-x=-(x-y)

After

norm(y-x)=abs(-1)*norm(x-y)=norm(x-y)

Conditions: none

Apply absolute homogeneity at scalar−1,not an inference from one pair of equal numeric distances.

Step identifiers and dependencies

Rule: norm_metric_symmetry_absolute_homogeneity · Uses: G001, S001

S003 · implies

Before

arbitrary x,y,z in R^12;x-z=(x-y)+(y-z)

After

d(x,z)<=d(x,y)+d(y,z) by norm triangle inequality

Conditions: none

The vector-difference identity and universal norm triangle inequality apply to every triple.This does not assert every metric is norm-induced or establish completeness.

Step identifiers and dependencies

Rule: norm_metric_triangle_universal_decomposition · Uses: G001, S002

S004 · implies

Before

norm=linfinity;dimension=12;selected evidence=named_formula_certificate

After

evidence sufficient=Yes;sample failure does not deny named formula metricity

Conditions: none

A universal named-norm certificate suffices;finite distance samples do not cover all points of the metric axioms.No judges the evidence insufficient,not the known named formula nonmetric.

Step identifiers and dependencies

Rule: induced_metric_evidence_mode_not_property_negation · Uses: G001, S003

Reverse checks

  • 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

(linfinity, 12, named_formula_certificate, Yes, universal_from_norm_axioms)

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: d71143945de731afbb17d460d579c020c8e6c016f681528fd879d7e6835d6da6
  • candidate record SHA-256: 53544451357df99c6796ddc0730e162e9bbb26a5ba53be934271750ae2d0bab4
  • semantic review receipt SHA-256: 0e51c2bf621e6e998415fdd75d260464e625cecd5894a230c9f09553249551c5
  • question-first witness SHA-256: ceb79401a62782c9f7e5ed86afee9b1a71455f799bd24cf485cba7aa8ecaca8a
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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