PA00CE

odd_sum_iff_opposite_parity

Alpha v16 checked-use theorem · independently closed; not Stable

A sum is odd exactly when its summands have opposite parity.

Exact expanded PA statement

forall m n. (((exists psc_odd_odd_sum. m + n = 2 * psc_odd_odd_sum + 1) -> ((((exists psc_even_even_m. m = 2 * psc_even_even_m) /\ (exists psc_odd_odd_n. n = 2 * psc_odd_odd_n + 1)) \/ ((exists psc_odd_odd_m. m = 2 * psc_odd_odd_m + 1) /\ (exists psc_even_even_n. n = 2 * psc_even_even_n))))) /\ (((((exists psc_even_even_m. m = 2 * psc_even_even_m) /\ (exists psc_odd_odd_n. n = 2 * psc_odd_odd_n + 1)) \/ ((exists psc_odd_odd_m. m = 2 * psc_odd_odd_m + 1) /\ (exists psc_even_even_n. n = 2 * psc_even_even_n)))) -> (exists psc_odd_odd_sum. m + n = 2 * psc_odd_odd_sum + 1)))

Structural proof guide

Generated structural guide

A sum is odd exactly when its summands have opposite parity.

Use the direct prerequisites odd_sum_parity_cases, even_add_odd, odd_add_even as previously established PA formulas.

The proof proceeds by case analysis (3).

Referenced ingredients

Proof neighborhood

Direct dependencies

Direct dependents

Formal native tactic body

Dependencies are introduced as named hypotheses before line 1. Linked names are exact direct references. This Alpha-v16 checked-use theorem is independently kernel-checked when replayed; it is not a Stable theorem.

  1. 0001intro m
  2. 0002intro n
  3. 0003split
  4. 0004intro hsum
  5. 0005specialize odd_sum_parity_cases m
  6. 0006specialize odd_sum_parity_cases n
  7. 0007apply odd_sum_parity_cases
  8. 0008exact hsum
  9. 0009intro hopposite
  10. 0010cases hopposite
  11. 0011cases hopposite_left
  12. 0012specialize even_add_odd m
  13. 0013specialize even_add_odd n
  14. 0014apply even_add_odd
  15. 0015exact hopposite_left_left
  16. 0016exact hopposite_left_right
  17. 0017cases hopposite_right
  18. 0018specialize odd_add_even m
  19. 0019specialize odd_add_even n
  20. 0020apply odd_add_even
  21. 0021exact hopposite_right_left
  22. 0022exact hopposite_right_right