DL0033

matrix_rank_no_index_below_zero

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

The empty finite domain has no index, by natural successor nonzeroness.

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 i. ~(exists mdr_gap_no_index. mdr_gap_no_index + S (i) = (0))

Constructive proof overview

Generated structural guide

The empty finite domain has no index, by natural successor nonzeroness.

The unchanged tactic script uses 2 declared prerequisites and contains 9 exact native proof lines.

Alpha v34 checked-use · first admitted v27 · independently kernel and Lean verified; not Stable

Proof neighborhood

Direct dependencies

le_zero Stable theorem; checked-use authorized succ_ne_zero 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

9 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 assumptionsL1–2

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

  1. L1
    intro i
  2. L2
    intro hi
02Establish hzeroL3–9

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

  1. L3
    have hzero : S i = 0
  2. L4
    specialize le_zero (S i)
  3. L5
    apply le_zero
  4. L6
    exact hi
  5. L7
    specialize succ_ne_zero (i)
  6. L8
    apply succ_ne_zero
  7. L9
    exact hzero

Library-wide reading audit

Original exact command ledger · 9 lines
  1. 0001intro i
  2. 0002intro hi
  3. 0003have hzero : S i = 0
  4. 0004specialize le_zero (S i)
  5. 0005apply le_zero
  6. 0006exact hi
  7. 0007specialize succ_ne_zero (i)
  8. 0008apply succ_ne_zero
  9. 0009exact hzero