BT0015

add_le_add_left

Stable ยท empty-context checked

Adding the same left summand preserves the witness-defined order.

Exact expanded PA statement

forall a b c. (exists k. k + a = b) -> exists r. r + (c + a) = c + b

Structural proof guide

Adding the same left summand preserves the witness-defined order.

Direct prerequisites: add_assoc, add_comm. The authored body proceeds by case analysis (1).

Proof neighborhood

Direct dependencies

Direct dependents

Formal native tactic body

Dependencies are hypotheses of this body receipt. The focused endpoint audits separately check the complete empty-context certificates.

  1. 0001intro a
  2. 0002intro b
  3. 0003intro c
  4. 0004intro h
  5. 0005cases h
  6. 0006exists x
  7. 0007trans (x + c) + a
  8. 0008symm
  9. 0009apply add_assoc
  10. 0010trans (c + x) + a
  11. 0011congr
  12. 0012apply add_comm
  13. 0013refl
  14. 0014trans c + (x + a)
  15. 0015apply add_assoc
  16. 0016congr
  17. 0017refl
  18. 0018exact h_witness