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| Mirrors > Home > MPE Home > Th. List > zeneo | Structured version Visualization version GIF version | ||
| Description: No even integer equals an odd integer (i.e. no integer can be both even and odd). Exercise 10(a) of [Apostol] p. 28. This variant of zneo 12685 follows immediately from the fact that a contradiction implies anything, see pm2.21i 120. (Contributed by AV, 22-Jun-2021.) |
| Ref | Expression |
|---|---|
| zeneo | ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → ((2 ∥ 𝐴 ∧ ¬ 2 ∥ 𝐵) → 𝐴 ≠ 𝐵)) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | nbrne1 5129 | . 2 ⊢ ((2 ∥ 𝐴 ∧ ¬ 2 ∥ 𝐵) → 𝐴 ≠ 𝐵) | |
| 2 | 1 | a1i 11 | 1 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → ((2 ∥ 𝐴 ∧ ¬ 2 ∥ 𝐵) → 𝐴 ≠ 𝐵)) |
| Colors of variables: wff setvar class |
| This proof depends on syntax axioms: ¬ wn 3 → wi 4 ∧ wa 400 ∈ wcel 2142 ≠ wne 2957 class class class wbr 5108 2c2 12301 ℤcz 12597 ∥ cdvds 16316 |
| This proof depends on axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1824 ax-4 1838 ax-5 1939 ax-6 1996 ax-7 2037 ax-8 2144 ax-9 2152 ax-ext 2734 |
| This proof depends on definitions: df-bi 210 df-an 401 df-or 861 df-3an 1104 df-tru 1572 df-fal 1582 df-ex 1809 df-sb 2096 df-clab 2741 df-cleq 2754 df-clel 2837 df-ne 2958 df-rab 3416 df-v 3456 df-dif 3907 df-un 3909 df-ss 3921 df-nul 4286 df-if 4487 df-sn 4589 df-pr 4591 df-op 4595 df-br 5109 |
| This theorem is used by: (None) |
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