EL0022

lte_strict_difference_nonzero

Alpha v34 independently verified · alpha_closed; checked-use authorized; not Stable

A witnessed strictly positive natural difference is nonzero.

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 first-order arithmetic statement

forall x y d. (exists olte_gap_strict_difference. olte_gap_strict_difference + S (y) = (x)) -> x = y + d -> ~(d = 0)

Constructive proof overview

Generated structural guide

A witnessed strictly positive natural difference is nonzero.

The unchanged tactic script uses 1 declared prerequisite and contains 15 exact native proof lines.

Alpha v34 checked-use · first admitted v29 · independently kernel and Lean verified; not Stable

Proof neighborhood

Direct dependencies

lt_irrefl_expanded Stable theorem; checked-use authorized

Direct dependents

Formal native tactic body

Dependencies are introduced as named hypotheses before line 1. Local theorem links identify exact declared prerequisites. This exact body belongs to a complete independently kernel-checked constructive proof bundle and has Alpha checked-use authority; it does not imply Stable membership.

Read the argument

Proof checkpoints

15 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.

01Fix variables and assumptionsL1–6

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

  1. L1
    intro x
  2. L2
    intro y
  3. L3
    intro d
  4. L4
    intro hgt
  5. L5
    intro hbalance
  6. L6
    intro hdzero
02Establish heqL7–15

Establish this local claim before using it. It is not an additional assumption. The following proof commands apply PA3.

  1. L7
    have heq : x = y
  2. L8
    trans y + d
  3. L9
    exact hbalance
  4. L10
    rewrite hdzero
  5. L11
    apply PA3
  6. L12
    rewrite heq at hgt
  7. L13
    specialize lt_irrefl_expanded (y)
  8. L14
    apply lt_irrefl_expanded
  9. L15
    exact hgt

Library-wide reading audit

Original exact command ledger · 15 lines
  1. 0001intro x
  2. 0002intro y
  3. 0003intro d
  4. 0004intro hgt
  5. 0005intro hbalance
  6. 0006intro hdzero
  7. 0007have heq : x = y
  8. 0008trans y + d
  9. 0009exact hbalance
  10. 0010rewrite hdzero
  11. 0011apply PA3
  12. 0012rewrite heq at hgt
  13. 0013specialize lt_irrefl_expanded (y)
  14. 0014apply lt_irrefl_expanded
  15. 0015exact hgt