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Question 10836: A Single Generator, Including the Zero-Vector Case

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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R0020-10836 · q-20261013-advance-20261023-r02-linear-combination-span-0086

Original question and givens

Use a declared finite generator family in a fixed real coordinate space. Preserve generator order, duplicates and its coefficient pairing; all vector dimensions and coefficient counts must match. A span quantifies over all finite linear combinations, not a fixed-arity sample or an undefined infinite series. generator=[2, 4], target=[0, 0]. Give (generator,target,scalar or status,in span?). For a nonzero generator, obtain the candidate scalar from its first nonzero coordinate and retain it even if another coordinate fails. For a zero generator, output any-scalar for a zero target, otherwise does-not-exist. Use exact reduced rational outputs with positive denominators, omitting /1 for integers.

  • G001 — Use a declared finite generator family in a fixed real coordinate space. Preserve generator order, duplicates and its coefficient pairing; all vector dimensions and coefficient counts must match. A span quantifies over all finite linear combinations, not a fixed-arity sample or an undefined infinite series. generator=[2, 4], target=[0, 0]. Give (generator,target,scalar or status,in span?). For a nonzero generator, obtain the candidate scalar from its first nonzero coordinate and retain it even if another coordinate fails. For a zero generator, output any-scalar for a zero target, otherwise does-not-exist. Use exact reduced rational outputs with positive denominators, omitting /1 for integers.

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

fixed real coordinate space;span uses all finite real linear combinations

After

given coefficient witness and existence of some coefficients are separate

Conditions: none

Span quantifies all finite real linear combinations.These integer/rational instances are declared slices;a failed designated witness does not show every coefficient choice fails.

Step identifiers and dependencies

Rule: span_quantifier_and_witness_scope · Uses: G001

S002 · calculation

Before

single-generator first nonzero pivot scalar := div(0, 2)

After

single-generator first nonzero pivot scalar = 0

Conditions: none

Compute exactly with this step's original roles and operands,without floating approximation or reordering source data.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S001

S003 · implies

Before

generator=[2, 4];target=[0, 0];first nonzero coordinate=0

After

necessary scalar=0

Conditions: none

The first nonzero pivot equation forces every possible scalar to equal this ratio,with a negative denominator normalized exactly.

Step identifiers and dependencies

Rule: single_generator_pivot_necessary_scalar · Uses: G001, S002

S004 · calculation

Before

single-generator coordinate0 scaled := mul(0, 2)

After

single-generator coordinate0 scaled = 0

Conditions: none

Compute exactly with this step's original roles and operands,without floating approximation or reordering source data.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · calculation

Before

single-generator coordinate0 residual := sub(0, 0)

After

single-generator coordinate0 residual = 0

Conditions: none

Compute exactly with this step's original roles and operands,without floating approximation or reordering source data.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

S006 · calculation

Before

single-generator coordinate1 scaled := mul(0, 4)

After

single-generator coordinate1 scaled = 0

Conditions: none

Compute exactly with this step's original roles and operands,without floating approximation or reordering source data.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S005

S007 · calculation

Before

single-generator coordinate1 residual := sub(0, 0)

After

single-generator coordinate1 residual = 0

Conditions: none

Compute exactly with this step's original roles and operands,without floating approximation or reordering source data.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S006

S008 · implies

Before

pivot scalar=0;all coordinate residuals=[0, 0]

After

in single-generator span=Yes;returned scalar remains=0

Conditions: none

Both directions matter:all equalities give a witness;if any fails,the pivot already forces the unique scalar,so no other scalar repairs it.Retain the candidate ratio even on failure as specified.

Step identifiers and dependencies

Rule: single_generator_all_coordinates_after_pivot · Uses: G001, S007

Reverse checks

  • 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 — Recompute single-generator coordinate1 residual with exact rational arithmetic, not rounded decimals.
  • S006 · premise_and_result_audit — Recompute single-generator coordinate1 scaled with exact rational arithmetic, not rounded decimals.
  • S005 · premise_and_result_audit — Recompute single-generator coordinate0 residual with exact rational arithmetic, not rounded decimals.
  • S004 · premise_and_result_audit — Recompute single-generator coordinate0 scaled 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 single-generator first nonzero pivot scalar 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.

Result

([2, 4], [0, 0], 0, Yes)

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: 08d649721cf492a3cf13826d5eb053860b4a6a131e8908ec91c94dc227fc599e
  • candidate record SHA-256: c7e997880622e13a8b8579d72a4c2d12e6e7d81ebfbc8e3ec649aa6883c5b368
  • semantic review receipt SHA-256: b4c47938fd38085d44967226cfa8337d61334455472e7307c60d3a488cef598f
  • question-first witness SHA-256: 3c23baa97a5933bc07b44f2257017ef4e845bf1429bd6f5381410681c43b97e4
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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