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| Mirrors > Home > ILE Home > Th. List > ge0nemnf | GIF version | ||
| Description: A nonnegative extended real is greater than negative infinity. (Contributed by Mario Carneiro, 20-Aug-2015.) |
| Ref | Expression |
|---|---|
| ge0nemnf | ⊢ ((𝐴 ∈ ℝ* ∧ 0 ≤ 𝐴) → 𝐴 ≠ -∞) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ge0gtmnf 10243 | . 2 ⊢ ((𝐴 ∈ ℝ* ∧ 0 ≤ 𝐴) → -∞ < 𝐴) | |
| 2 | ngtmnft 10237 | . . . . 5 ⊢ (𝐴 ∈ ℝ* → (𝐴 = -∞ ↔ ¬ -∞ < 𝐴)) | |
| 3 | 2 | adantr 276 | . . . 4 ⊢ ((𝐴 ∈ ℝ* ∧ 0 ≤ 𝐴) → (𝐴 = -∞ ↔ ¬ -∞ < 𝐴)) |
| 4 | 3 | biimpd 144 | . . 3 ⊢ ((𝐴 ∈ ℝ* ∧ 0 ≤ 𝐴) → (𝐴 = -∞ → ¬ -∞ < 𝐴)) |
| 5 | 4 | necon2ad 2477 | . 2 ⊢ ((𝐴 ∈ ℝ* ∧ 0 ≤ 𝐴) → (-∞ < 𝐴 → 𝐴 ≠ -∞)) |
| 6 | 1, 5 | mpd 13 | 1 ⊢ ((𝐴 ∈ ℝ* ∧ 0 ≤ 𝐴) → 𝐴 ≠ -∞) |
| Colors of variables: wff set class |
| This proof depends on syntax axioms: ¬ wn 3 → wi 4 ∧ wa 104 ↔ wb 105 = wceq 1402 ∈ wcel 2209 ≠ wne 2420 class class class wbr 4131 0cc0 8186 -∞cmnf 8365 ℝ*cxr 8366 < clt 8367 ≤ cle 8368 |
| This proof depends on axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-in1 623 ax-in2 624 ax-io 721 ax-5 1500 ax-7 1501 ax-gen 1502 ax-ie1 1546 ax-ie2 1547 ax-8 1557 ax-10 1558 ax-11 1559 ax-i12 1560 ax-bndl 1562 ax-4 1563 ax-17 1579 ax-i9 1583 ax-ial 1587 ax-i5r 1588 ax-14 2212 ax-ext 2220 ax-sep 4251 ax-pow 4313 ax-pr 4348 ax-un 4580 ax-setind 4686 ax-cnex 8277 ax-resscn 8278 ax-1re 8280 ax-addrcl 8283 ax-rnegex 8295 ax-pre-ltirr 8298 ax-pre-ltwlin 8299 ax-pre-lttrn 8300 |
| This proof depends on definitions: df-bi 117 df-3or 1010 df-3an 1011 df-tru 1405 df-fal 1408 df-nf 1514 df-sb 1816 df-eu 2089 df-mo 2090 df-clab 2225 df-cleq 2231 df-clel 2234 df-nfc 2381 df-ne 2421 df-nel 2516 df-ral 2533 df-rex 2534 df-rab 2537 df-v 2823 df-dif 3222 df-un 3224 df-in 3226 df-ss 3233 df-pw 3690 df-sn 3715 df-pr 3716 df-op 3718 df-uni 3936 df-br 4132 df-opab 4194 df-po 4443 df-iso 4444 df-xp 4782 df-cnv 4784 df-pnf 8369 df-mnf 8370 df-xr 8371 df-ltxr 8372 df-le 8373 |
| This theorem is used by: xlesubadd 10303 xrbdtri 12068 isxmet2d 15586 xmetrtri 15614 xblpnfps 15636 xblpnf 15637 xblss2ps 15642 xblss2 15643 |
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