PA006T · theorem

odd_half_unique

Stable checked-use theorem · independently closed

The half witness in an odd decomposition is unique.

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 n a b. n = 2 * a + 1 -> n = 2 * b + 1 -> a = b

Every purple notation token opens its conservative definition. This is a reading surface; the compiler expands the statement before the unchanged kernel checks it.

Definitions used by this theorem

In the theorem statement

none

0 occurrences

In local proof propositions

none

0 occurrences

Exact expanded native-PA statement
forall n a b. n = 2 * a + 1 -> n = 2 * b + 1 -> a = b

Proof neighborhood

Direct theorem prerequisites

Direct theorem dependents

Definition-aware tactic body

Only local propositions introduced by have or suffices are compacted. The untrusted compiler re-expands each one before the original tactic script is replayed; defined notation is never accepted by the kernel. Open the exact replay line beneath every changed command.

Read the argument

Proof checkpoints

24 script commands · 5 reading checkpoints · 2 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 (2)
01Fix variables and assumptionsL1–5

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

  1. L1
    intro n
  2. L2
    intro a
  3. L3
    intro b
  4. L4
    intro ha
  5. L5
    intro hb
02Establish hsL6–10

Establish this local claim before using it. It is not an additional assumption.

  1. L6
    have hs : 2 * a + 1 = 2 * b + 1
  2. L7
    trans n
  3. L8
    symm
  4. L9
    exact ha
  5. L10
    exact hb
03Establish hmL11–20

Establish this local claim before using it. It is not an additional assumption. The following proof commands apply add right cancel.

  1. L11
    have hm : 2 * a = 2 * b
  2. L12
    specialize add_right_cancel (2 * a)
  3. L13
    specialize add_right_cancel (2 * b)
  4. L14
    specialize add_right_cancel 1
  5. L15
    apply add_right_cancel
  6. L16
    exact hs
  7. L17
    specialize mul_left_cancel_nonzero 2
  8. L18
    specialize mul_left_cancel_nonzero a
  9. L19
    specialize mul_left_cancel_nonzero b
  10. L20
    apply mul_left_cancel_nonzero
04Fix variables and assumptionsL21–21

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

  1. L21
    intro htwo
05Use earlier factsL22–24

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

  1. L22
    apply PA1
  2. L23
    exact htwo
  3. L24
    exact hm

Library-wide reading audit

Original defined command ledger · 24 lines
  1. 0001intro n
  2. 0002intro a
  3. 0003intro b
  4. 0004intro ha
  5. 0005intro hb
  6. 0006have hs : 2 * a + 1 = 2 * b + 1
  7. 0007trans n
  8. 0008symm
  9. 0009exact ha
  10. 0010exact hb
  11. 0011have hm : 2 * a = 2 * b
  12. 0012specialize add_right_cancel (2 * a)
  13. 0013specialize add_right_cancel (2 * b)
  14. 0014specialize add_right_cancel 1
  15. 0015apply add_right_cancel
  16. 0016exact hs
  17. 0017specialize mul_left_cancel_nonzero 2
  18. 0018specialize mul_left_cancel_nonzero a
  19. 0019specialize mul_left_cancel_nonzero b
  20. 0020apply mul_left_cancel_nonzero
  21. 0021intro htwo
  22. 0022apply PA1
  23. 0023exact htwo
  24. 0024exact hm