PF0002 · theorem body

pythagorean_euclidean_constructor

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

Every witnessed natural square difference constructs an explicit Euclidean Pythagorean triple.

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.

Statement with defined notation

∀ m. ∀ n. (∃ x. m · m = n · n + x) → ∃ x. Pythagorean(x,2 · (m · n),m · m + n · n)

Every purple notation token opens its conservative definition. This reading surface never changes the unchanged intuitionistic kernel or confers checked-use authority.

Definitions used by this theorem

In the theorem statement

In local proof propositions

none
Exact expanded first-order statement
forall m n. (exists d. m * m = n * n + d) -> exists d. ((d) * (d) + (2 * (m * n)) * (2 * (m * n)) = (m * m + n * n) * (m * m + n * n))

Proof neighborhood

Direct theorem prerequisites

Direct theorem dependents

Definition-aware tactic body

Only propositions whose conservative expansion has been checked for exact first-order equivalence are compacted. Every changed line retains its immutable exact replay command.

Read the argument

Proof checkpoints

7 script commands · 4 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.

Definition notation is shown below. Open the paired exact edition for the original native formulas. Source pairing is not a new equivalence certificate.

Named ingredients (1)
01Fix variables and assumptionsL1–3

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

  1. L1
    intro m
  2. L2
    intro n
  3. L3
    intro hgap
02Separate the logical casesL4–4

Follow the explicit conjunction, disjunction, witness, or contradiction step recorded below.

  1. L4
    cases hgap
03Construct an explicit witnessL5–5

Supply the displayed value, then prove that it has the required property.

  1. L5
    exists x
04Use earlier factsL6–7

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

  1. L6
    apply pythagorean_euclidean_identity
  2. L7
    exact hgap_witness

Library-wide reading audit

Original defined command ledger · 7 lines
  1. 0001intro m
  2. 0002intro n
  3. 0003intro hgap
  4. 0004cases hgap
  5. 0005exists x
  6. 0006apply pythagorean_euclidean_identity
  7. 0007exact hgap_witness