BT001D · Bertrand theorem

lt_of_lt_of_le

Stable checked-use theorem · independently kernel verified

Strict order followed by weak order remains strict.

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. ∀ b. ∀ c. Lt(a,b)Le(b,c)Lt(a,c)

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

3 occurrences

In local proof propositions

none

0 occurrences

Exact expanded native-PA statement
forall a b c. (exists k. k + S a = b) -> (exists k. k + b = c) -> exists k. k + S a = c

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

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.

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 (1)
01Fix variables and assumptionsL1–5

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

  1. L1
    intro a
  2. L2
    intro b
  3. L3
    intro c
  4. L4
    intro hab
  5. L5
    intro hbc
02Use earlier factsL6–11

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

  1. L6
    specialize le_trans (S a)
  2. L7
    specialize le_trans b
  3. L8
    specialize le_trans c
  4. L9
    apply le_trans
  5. L10
    exact hab
  6. L11
    exact hbc

Library-wide reading audit

Original defined command ledger · 11 lines
  1. 0001intro a
  2. 0002intro b
  3. 0003intro c
  4. 0004intro hab
  5. 0005intro hbc
  6. 0006specialize le_trans (S a)
  7. 0007specialize le_trans b
  8. 0008specialize le_trans c
  9. 0009apply le_trans
  10. 0010exact hab
  11. 0011exact hbc