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 p n P N. p + N = P + n -> ~(p = n) -> ~(P = N)Constructive proof overview
Generated structural guide
Nonzeroness of the represented integer is preserved by cross-sum equality, using actual additive cancellation.
The unchanged tactic script uses 2 declared prerequisites and contains 16 exact native proof lines.
Alpha v34 checked-use · first admitted v27 · independently kernel and Lean verified; not Stable
Proof neighborhood
Direct dependencies
add_right_cancel Stable theorem; checked-use authorized add_comm Stable theorem; checked-use authorizedDirect 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 assumptionsL1–7
02Use earlier factsL8–12
03Calculate and transport equalitiesL13–13
Carry out the recorded arithmetic or equality steps; inspect the exact commands for their direction and premises.
- L13
trans P + n
04Use earlier factsL14–14
Instantiate or apply named facts and discharge the corresponding proof obligations.
- L14
exact hbalance
05Calculate and transport equalitiesL15–15
Carry out the recorded arithmetic or equality steps; inspect the exact commands for their direction and premises.
- L15
rewrite hzero
06Use earlier factsL16–16
Instantiate or apply named facts and discharge the corresponding proof obligations.
- L16
apply add_comm
Original exact command ledger · 16 lines
- 0001
intro p - 0002
intro n - 0003
intro P - 0004
intro N - 0005
intro hbalance - 0006
intro hnonzero - 0007
intro hzero - 0008
apply hnonzero - 0009
specialize add_right_cancel (p) - 0010
specialize add_right_cancel (n) - 0011
specialize add_right_cancel (N) - 0012
apply add_right_cancel - 0013
trans P + n - 0014
exact hbalance - 0015
rewrite hzero - 0016
apply add_comm