BT0125

bertrand_closed_upper

Alpha v34 checked-use theorem · independently kernel and Lean verified; not Stable

Every nonzero natural has a prime in its open-closed Bertrand interval.

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 PA statement

forall n. ~(n = 0) -> exists p. ((~(p = 1) /\ forall a b. p = a * b -> a = 1 \/ b = 1) /\ ((exists u. u + S n = p) /\ (exists v. v + p = n + n)))

Structural proof guide

Every nonzero natural has a prime in its open-closed Bertrand interval.

Direct prerequisites: le_or_lt, bertrand_eventually_closed_upper, bertrand_small_closed_upper. The authored body proceeds by case analysis (1).

Proof neighborhood

Direct dependencies

Direct dependents

Formal native tactic body

Dependencies are hypotheses of the historical Alpha-v12 body receipt. The complete historical Alpha-v18 proof bundle independently checks every dependency; current Alpha v25 preserves that checked theorem use without changing Stable membership.

Read the argument

Proof checkpoints

12 script commands · 4 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.

Named ingredients (3)
01Fix variables and assumptionsL1–2

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

  1. L1
    intro n
  2. L2
    intro hnonzero
02Use earlier factsL3–4

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

  1. L3
    specialize le_or_lt (16 * 32)
  2. L4
    specialize le_or_lt n
03Separate the logical casesL5–5

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

  1. L5
    cases le_or_lt
04Use earlier factsL6–12

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

  1. L6
    specialize bertrand_eventually_closed_upper n
  2. L7
    apply bertrand_eventually_closed_upper
  3. L8
    exact le_or_lt_left
  4. L9
    specialize bertrand_small_closed_upper n
  5. L10
    apply bertrand_small_closed_upper
  6. L11
    exact hnonzero
  7. L12
    exact le_or_lt_right

Library-wide reading audit

Original exact command ledger · 12 lines
  1. 0001intro n
  2. 0002intro hnonzero
  3. 0003specialize le_or_lt (16 * 32)
  4. 0004specialize le_or_lt n
  5. 0005cases le_or_lt
  6. 0006specialize bertrand_eventually_closed_upper n
  7. 0007apply bertrand_eventually_closed_upper
  8. 0008exact le_or_lt_left
  9. 0009specialize bertrand_small_closed_upper n
  10. 0010apply bertrand_small_closed_upper
  11. 0011exact hnonzero
  12. 0012exact le_or_lt_right