PF0007 · theorem body

pythagorean_difference_witness_unique

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

The natural Euclidean square-difference coordinate is unique without subtraction or classical choice.

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

forall m n d e. m * m = n * n + d -> m * m = n * n + e -> d = e

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

none

In local proof propositions

none
Exact expanded first-order statement
forall m n d e. m * m = n * n + d -> m * m = n * n + e -> d = e

Proof neighborhood

Direct theorem prerequisites

add_left_cancel · Stable closed

Direct theorem dependents

none

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

14 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.

01Fix variables and assumptionsL1–6

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

  1. L1
    intro m
  2. L2
    intro n
  3. L3
    intro d
  4. L4
    intro e
  5. L5
    intro hd
  6. L6
    intro he
02Use earlier factsL7–10

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

  1. L7
    specialize add_left_cancel (n * n)
  2. L8
    specialize add_left_cancel d
  3. L9
    specialize add_left_cancel e
  4. L10
    apply add_left_cancel
03Calculate and transport equalitiesL11–12

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

  1. L11
    trans m * m
  2. L12
    symm
04Use earlier factsL13–14

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

  1. L13
    exact hd
  2. L14
    exact he

Library-wide reading audit

Original defined command ledger · 14 lines
  1. 0001intro m
  2. 0002intro n
  3. 0003intro d
  4. 0004intro e
  5. 0005intro hd
  6. 0006intro he
  7. 0007specialize add_left_cancel (n * n)
  8. 0008specialize add_left_cancel d
  9. 0009specialize add_left_cancel e
  10. 0010apply add_left_cancel
  11. 0011trans m * m
  12. 0012symm
  13. 0013exact hd
  14. 0014exact he