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Question 12605: The Norm of an Ordered Vector Difference

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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R0024-12605 · q-20261013-advance-20261026-r02-real-normed-vector-space-0080

Original question and givens

Only the named real-coordinate formulas l1(v)=sum_i |v_i| and linfinity(v)=max_i |v_i| are supported here. Their universal algebraic certificates, not a finite sample, supply the norm axioms. An unsupported name is outside this protocol, not a claim that every other formula fails to be a norm. norm_name=l1, left=[-8, 1, -4], right=[8, 1, -2] with equal dimension. Give (norm_name,left,right,left−right,distance).

  • G001 — Only the named real-coordinate formulas l1(v)=sum_i |v_i| and linfinity(v)=max_i |v_i| are supported here. Their universal algebraic certificates, not a finite sample, supply the norm axioms. An unsupported name is outside this protocol, not a claim that every other formula fails to be a norm. norm_name=l1, left=[-8, 1, -4], right=[8, 1, -2] with equal dimension. Give (norm_name,left,right,left−right,distance).

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

distance coordinate0 left-minus-right := sub(-8, 8)

After

distance coordinate0 left-minus-right = -16

Conditions: none

Compute exactly from the original roles and complete established operands,without changing pairings,order or replacing guards by approximation.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001

S002 · calculation

Before

distance coordinate1 left-minus-right := sub(1, 1)

After

distance coordinate1 left-minus-right = 0

Conditions: none

Compute exactly from the original roles and complete established operands,without changing pairings,order or replacing guards by approximation.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S001

S003 · calculation

Before

distance coordinate2 left-minus-right := sub(-4, -2)

After

distance coordinate2 left-minus-right = -2

Conditions: none

Compute exactly from the original roles and complete established operands,without changing pairings,order or replacing guards by approximation.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · implies

Before

named certified norm=l1;left=[-8, 1, -4];right=[8, 1, -2]

After

ordered difference=[-16, 0, -2];distance=norm(left-right)

Conditions: none

Use the same named norm on the same coordinate space and retain the difference direction.This does not assert every metric is norm-induced,or add completeness or inner-product claims.

Step identifiers and dependencies

Rule: fixed_norm_induced_distance_scope · Uses: G001, S003

S005 · implies

Before

induced distance:coordinate=0;signed value=-16

After

absolute value=16

Conditions: none

Take the absolute value of each entire coordinate.Negative coordinates are not summed or maximized as signed values;retain the original signed vector.

Step identifiers and dependencies

Rule: named_norm_each_coordinate_absolute_value · Uses: G001, S004

S006 · implies

Before

induced distance:coordinate=1;signed value=0

After

absolute value=0

Conditions: none

Take the absolute value of each entire coordinate.Negative coordinates are not summed or maximized as signed values;retain the original signed vector.

Step identifiers and dependencies

Rule: named_norm_each_coordinate_absolute_value · Uses: G001, S005

S007 · implies

Before

induced distance:coordinate=2;signed value=-2

After

absolute value=2

Conditions: none

Take the absolute value of each entire coordinate.Negative coordinates are not summed or maximized as signed values;retain the original signed vector.

Step identifiers and dependencies

Rule: named_norm_each_coordinate_absolute_value · Uses: G001, S006

S008 · calculation

Before

induced distance l1 sum := sum(16, 0, 2)

After

induced distance l1 sum = 18

Conditions: none

Compute exactly from the original roles and complete established operands,without changing pairings,order or replacing guards by approximation.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S007

Reverse checks

  • S008 · premise_and_result_audit — Recompute induced distance l1 sum 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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S003 · premise_and_result_audit — Recompute distance coordinate2 left-minus-right with exact rational arithmetic, not rounded decimals.
  • S002 · premise_and_result_audit — Recompute distance coordinate1 left-minus-right with exact rational arithmetic, not rounded decimals.
  • S001 · premise_and_result_audit — Recompute distance coordinate0 left-minus-right with exact rational arithmetic, not rounded decimals.

Result

(l1, [-8, 1, -4], [8, 1, -2], [-16, 0, -2], 18)

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: 1be4a5893e8d21292c90c841c38b760dd2bb8e97d660144f8cc6580990647d8b
  • candidate record SHA-256: c150b7d1915d65227b092f7e208df3c1e39b57508b4d73736d94ab68dec3f70a
  • semantic review receipt SHA-256: 1c8f6c2c6c75852cb93c08235684ce9f32ebe86065c58c693a04257e772c2d35
  • question-first witness SHA-256: 05fd764b5f9f7fff6185003efe576d87632f6daf40606ac3839a7feafe4f80d8
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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