GT000A

euclidean_gcd_zero_terminal_unique

Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable

Any relational gcd at a zero-remainder terminal state is exactly its nonzero-side dividend, including a=0.

Current library: Alpha v34, 4,223 checked-use theorems; Stable remains 432. Historical first admissions, original proof editions, and non-admitted aliases are preserved. Exact original first-admission records.

Exact expanded first-order arithmetic statement

forall g a. ((((exists ec_gcd_left_egt_zero. a = g * ec_gcd_left_egt_zero) /\ (exists ec_gcd_right_egt_zero. 0 = g * ec_gcd_right_egt_zero)) /\ forall ec_gcd_common_egt_zero. (exists ec_gcd_common_left_egt_zero. a = ec_gcd_common_egt_zero * ec_gcd_common_left_egt_zero) -> (exists ec_gcd_common_right_egt_zero. 0 = ec_gcd_common_egt_zero * ec_gcd_common_right_egt_zero) -> exists ec_gcd_greatest_egt_zero. g = ec_gcd_common_egt_zero * ec_gcd_greatest_egt_zero)) -> g = a

Constructive proof overview

Generated structural guide

Any relational gcd at a zero-remainder terminal state is exactly its nonzero-side dividend, including a=0.

The unchanged tactic script uses 2 declared prerequisites and contains 11 exact native proof lines.

Alpha v34 checked-use · first admitted v22 · independently kernel and Lean verified; not Stable

Proof neighborhood

Direct dependencies

is_gcd_zero_right Stable theorem; checked-use authorized is_gcd_unique Stable theorem; checked-use authorized

Direct dependents

none

Formal native tactic body

Dependencies are introduced as named hypotheses before line 1. Local theorem links identify exact declared prerequisites. This exact body belongs to a complete independently kernel-checked constructive proof bundle and has Alpha checked-use authority; it does not imply Stable membership.

Read the argument

Proof checkpoints

11 script commands · 2 reading checkpoints · 0 local claims

This is a reading aid, not a new proof or a proof-tree certificate. Checkpoint groups are consecutive commands, not inferred branch boundaries. Every step links to the preserved script.

01Fix variables and assumptionsL1–3

Work with arbitrary variables or the premises of the current implication.

  1. L1
    intro g
  2. L2
    intro a
  3. L3
    intro hg
02Use earlier factsL4–11

Instantiate or apply named facts and discharge the corresponding proof obligations.

  1. L4
    specialize is_gcd_unique g
  2. L5
    specialize is_gcd_unique a
  3. L6
    specialize is_gcd_unique a
  4. L7
    specialize is_gcd_unique 0
  5. L8
    apply is_gcd_unique
  6. L9
    exact hg
  7. L10
    specialize is_gcd_zero_right a
  8. L11
    exact is_gcd_zero_right

Library-wide reading audit

Original exact command ledger · 11 lines
  1. 0001intro g
  2. 0002intro a
  3. 0003intro hg
  4. 0004specialize is_gcd_unique g
  5. 0005specialize is_gcd_unique a
  6. 0006specialize is_gcd_unique a
  7. 0007specialize is_gcd_unique 0
  8. 0008apply is_gcd_unique
  9. 0009exact hg
  10. 0010specialize is_gcd_zero_right a
  11. 0011exact is_gcd_zero_right