PF002O

fermat_four_no_fourth

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

Fermat's last theorem for exponent four holds unconditionally for every positive natural triple in unchanged Heyting arithmetic.

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 a b h. ~(a = 0) -> ~(b = 0) -> ~(h = 0) -> ~(a * a * a * a + b * b * b * b = h * h * h * h)

Constructive proof overview

Generated structural guide

Fermat's last theorem for exponent four holds unconditionally for every positive natural triple in unchanged Heyting arithmetic.

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

dependency-curried kernel-checked theorem body; Alpha enrollment and checked-use authority follow separately sealed release evidence; Stable membership remains unchanged

Proof neighborhood

Direct dependencies

Direct dependents

none

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

2 script commands · 1 reading checkpoints · 0 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.

Named ingredients (2)
01Use earlier factsL1–2

Instantiate or apply named facts and discharge the corresponding proof obligations.

  1. L1
    apply fermat_four_no_fourth_from_descent
  2. L2
    exact fermat_four_strict_descent_proved

Library-wide reading audit

Original exact command ledger · 2 lines
  1. 0001apply fermat_four_no_fourth_from_descent
  2. 0002exact fermat_four_strict_descent_proved