BT001I

lt_not_le

Stable ยท empty-context checked

A strict inequality excludes the reverse weak inequality.

Exact expanded PA statement

forall a b. (exists k. k + S a = b) -> ~ (exists k. k + b = a)

Structural proof guide

A strict inequality excludes the reverse weak inequality.

Direct prerequisites: none. The authored body proceeds by structural induction (1), case analysis (2), intermediate claims (1), equality transport (5).

Proof neighborhood

Direct dependencies

none

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. 0001have hbad : forall z u v. ~(z = u + (v + S z))
  2. 0002intro z
  3. 0003induction z
  4. 0004intro u
  5. 0005intro v
  6. 0006intro hz
  7. 0007apply PA1
  8. 0008symm
  9. 0009rewrite PA4 at hz
  10. 0010rewrite PA4 at hz
  11. 0011exact hz
  12. 0012intro u
  13. 0013intro v
  14. 0014intro hz
  15. 0015specialize IH u
  16. 0016specialize IH v
  17. 0017apply IH
  18. 0018apply PA2
  19. 0019rewrite PA4 at hz
  20. 0020rewrite PA4 at hz
  21. 0021exact hz
  22. 0022intro a
  23. 0023intro b
  24. 0024intro hab
  25. 0025intro hba
  26. 0026cases hab
  27. 0027cases hba
  28. 0028specialize hbad a
  29. 0029specialize hbad x1
  30. 0030specialize hbad x
  31. 0031apply hbad
  32. 0032symm
  33. 0033rewrite <- hab_witness at hba_witness
  34. 0034exact hba_witness