PA001F · theorem

is_gcd_zero_right

Stable checked-use theorem · independently closed

Every natural is the relational gcd of itself and zero.

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.

Statement with defined notation

∀ a. IsGCD(a,a,0)

Every purple notation token opens its conservative definition. This is a reading surface; the compiler expands the statement before the unchanged kernel checks it.

Definitions used by this theorem

In the theorem statement

1 occurrences

In local proof propositions

none

0 occurrences

Exact expanded native-PA statement
forall a. (((exists x. a = a * x) /\ (exists y. 0 = a * y)) /\ forall c. (exists u. a = c * u) -> (exists v. 0 = c * v) -> exists w. a = c * w)

Proof neighborhood

Direct theorem prerequisites

Direct theorem dependents

Definition-aware tactic body

Only local propositions introduced by have or suffices are compacted. The untrusted compiler re-expands each one before the original tactic script is replayed; defined notation is never accepted by the kernel. Open the exact replay line beneath every changed command.

Read the argument

Proof checkpoints

11 script commands · 5 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.

Definition notation is shown below. Open the paired exact edition for the original native formulas. Source pairing is not a new equivalence certificate.

Named ingredients (2)
01Fix variables and assumptionsL1–1

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

  1. L1
    intro a
02Separate the logical casesL2–3

Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.

  1. L2
    split
  2. L3
    split
03Use earlier factsL4–7

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

  1. L4
    specialize multiple_refl a
  2. L5
    exact multiple_refl
  3. L6
    specialize multiple_zero a
  4. L7
    exact multiple_zero
04Fix variables and assumptionsL8–10

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

  1. L8
    intro c
  2. L9
    intro ha
  3. L10
    intro hz
05Use earlier factsL11–11

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

  1. L11
    exact ha

Library-wide reading audit

Original defined command ledger · 11 lines
  1. 0001intro a
  2. 0002split
  3. 0003split
  4. 0004specialize multiple_refl a
  5. 0005exact multiple_refl
  6. 0006specialize multiple_zero a
  7. 0007exact multiple_zero
  8. 0008intro c
  9. 0009intro ha
  10. 0010intro hz
  11. 0011exact ha