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 b. (b = 0 \/ b = 1) -> exists gap. gap + S b = 2Constructive proof overview
Generated structural guide
Every witnessed binary digit is strictly below two.
The unchanged tactic script uses 0 declared prerequisites and contains 9 exact native proof lines.
Alpha v34 checked-use · first admitted v22 · independently kernel and Lean verified; not Stable
Proof neighborhood
Direct dependencies
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
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
02Separate the logical casesL3–3
Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.
- L3
cases hbit
03Construct an explicit witnessL4–4
Supply the displayed value, then prove that it has the required property.
- L4
exists 1
04Calculate and transport equalitiesL5–6
05Construct an explicit witnessL7–7
Supply the displayed value, then prove that it has the required property.
- L7
exists 0