PA003D · theorem

finite_lt_succ_eq_or_lt

Stable checked-use theorem · independently closed

A value below a successor is the predecessor or lies below it.

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. ∀ x. Lt(x,S n) → x = n ∨ Lt(x,n)

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

2 occurrences

In local proof propositions

1 occurrences

Exact expanded native-PA statement
forall n x. (exists h. h + S x = S n) -> x = n \/ exists h. h + S x = n

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

12 script commands · 2 reading checkpoints · 1 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 x
  3. L3
    intro hlt
02Establish hleL4–12

Establish this local claim before using it. It is not an additional assumption. The following proof commands apply le of succ le succ.

  1. L4
  2. L5
    specialize le_of_succ_le_succ x
  3. L6
    specialize le_of_succ_le_succ n
  4. L7
    apply le_of_succ_le_succ
  5. L8
    exact hlt
  6. L9
    specialize le_eq_or_lt x
  7. L10
    specialize le_eq_or_lt n
  8. L11
    apply le_eq_or_lt
  9. L12
    exact hle

Library-wide reading audit

Original defined command ledger · 12 lines
  1. 0001intro n
  2. 0002intro x
  3. 0003intro hlt
  4. 0004have hle : Le(x,n)
    Exact native replay linehave hle : exists h. h + x = n
  5. 0005specialize le_of_succ_le_succ x
  6. 0006specialize le_of_succ_le_succ n
  7. 0007apply le_of_succ_le_succ
  8. 0008exact hlt
  9. 0009specialize le_eq_or_lt x
  10. 0010specialize le_eq_or_lt n
  11. 0011apply le_eq_or_lt
  12. 0012exact hle