PA003D

finite_lt_succ_eq_or_lt

Stable checked-use theorem · independently closed

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

Exact expanded PA statement

forall n x. (exists h. h + S x = S n) -> x = n \/ exists h. h + S x = n

Structural proof guide

Generated structural guide

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

Use the direct prerequisites le_of_succ_le_succ, le_eq_or_lt as previously established PA formulas.

The proof proceeds by intermediate claims (1).

Referenced ingredients

Proof neighborhood

Direct dependencies

Direct dependents

Formal native tactic body

Dependencies are introduced as named hypotheses before line 1. Linked names are exact direct references. This Stable checked-use theorem is independently kernel-checked when replayed.

  1. 0001intro n
  2. 0002intro x
  3. 0003intro hlt
  4. 0004have 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