BT003L · Bertrand theorem

prime_divisor_exists

Stable checked-use theorem · independently kernel verified

Every nonzero nonunit natural has a prime divisor.

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

∀ n. ¬n = 0 → ¬n = 1 → ∃ x. Prime(x)Dvd(x,n)

Every purple notation token opens its conservative definition. Expanding the displayed statement recovers the exact first-order Peano-arithmetic formula checked by the unchanged kernel.

Definitions used by this theorem

In the theorem statement

2 occurrences

In local proof propositions

none

0 occurrences

Exact expanded native-PA statement
forall n. ~(n = 0) -> ~(n = 1) -> exists p. ((~(p = 1) /\ forall a b. p = a * b -> a = 1 \/ b = 1) /\ exists k. n = p * k)

Proof neighborhood

Direct theorem prerequisites

Direct theorem dependents

Definition-aware tactic body

Only local propositions introduced by have or suffices are compacted. Every changed line has an exact-AST conservative-expansion receipt; the kernel still receives the immutable original tactic script.

Read the argument

Proof checkpoints

9 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.

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 assumptionsL1–3

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

  1. L1
    intro n
  2. L2
    intro hn0
  3. L3
    intro hn1
02Use earlier factsL4–9

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

  1. L4
    specialize prime_divisor_exists_up_to n
  2. L5
    specialize prime_divisor_exists_up_to n
  3. L6
    apply prime_divisor_exists_up_to
  4. L7
    apply le_refl
  5. L8
    exact hn0
  6. L9
    exact hn1

Library-wide reading audit

Original defined command ledger · 9 lines
  1. 0001intro n
  2. 0002intro hn0
  3. 0003intro hn1
  4. 0004specialize prime_divisor_exists_up_to n
  5. 0005specialize prime_divisor_exists_up_to n
  6. 0006apply prime_divisor_exists_up_to
  7. 0007apply le_refl
  8. 0008exact hn0
  9. 0009exact hn1