PF0003

pythagorean_leg_swap

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

Swapping the two legs of a natural Pythagorean triple preserves its exact equation.

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 z. ((x) * (x) + (y) * (y) = (z) * (z)) -> ((y) * (y) + (x) * (x) = (z) * (z))

Constructive proof overview

Generated structural guide

Swapping the two legs of a natural Pythagorean triple preserves its exact equation.

The unchanged tactic script uses 1 declared prerequisite and contains 7 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

add_comm 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

7 script commands · 3 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.

01Fix variables and assumptionsL1–4

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

  1. L1
    intro x
  2. L2
    intro y
  3. L3
    intro z
  4. L4
    intro htriple
02Calculate and transport equalitiesL5–5

Carry out the recorded arithmetic or equality steps; inspect the exact commands for their direction and premises.

  1. L5
    trans x * x + y * y
03Use earlier factsL6–7

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

  1. L6
    apply add_comm
  2. L7
    exact htriple

Library-wide reading audit

Original exact command ledger · 7 lines
  1. 0001intro x
  2. 0002intro y
  3. 0003intro z
  4. 0004intro htriple
  5. 0005trans x * x + y * y
  6. 0006apply add_comm
  7. 0007exact htriple