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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 12707 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 5128 | . 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 401 ∈ wcel 2145 ≠ wne 2957 class class class wbr 5107 2c2 12322 ℤcz 12618 ∥ cdvds 16346 |
| This proof depends on axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1828 ax-4 1842 ax-5 1943 ax-6 2000 ax-7 2041 ax-8 2147 ax-9 2155 ax-ext 2734 |
| This proof depends on definitions: df-bi 210 df-an 402 df-or 862 df-3an 1105 df-tru 1573 df-fal 1583 df-ex 1813 df-sb 2100 df-clab 2741 df-cleq 2754 df-clel 2837 df-ne 2958 df-rab 3415 df-v 3455 df-dif 3905 df-un 3907 df-ss 3919 df-nul 4283 df-if 4486 df-sn 4588 df-pr 4590 df-op 4594 df-br 5108 |
| This theorem is used by: (None) |
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