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Mirrors > Home > ILE Home > Th. List > xnn0xr | GIF version |
Description: An extended nonnegative integer is an extended real. (Contributed by AV, 10-Dec-2020.) |
Ref | Expression |
---|---|
xnn0xr | ⊢ (𝐴 ∈ ℕ0* → 𝐴 ∈ ℝ*) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elxnn0 9010 | . 2 ⊢ (𝐴 ∈ ℕ0* ↔ (𝐴 ∈ ℕ0 ∨ 𝐴 = +∞)) | |
2 | nn0re 8954 | . . . 4 ⊢ (𝐴 ∈ ℕ0 → 𝐴 ∈ ℝ) | |
3 | 2 | rexrd 7783 | . . 3 ⊢ (𝐴 ∈ ℕ0 → 𝐴 ∈ ℝ*) |
4 | pnfxr 7786 | . . . 4 ⊢ +∞ ∈ ℝ* | |
5 | eleq1 2180 | . . . 4 ⊢ (𝐴 = +∞ → (𝐴 ∈ ℝ* ↔ +∞ ∈ ℝ*)) | |
6 | 4, 5 | mpbiri 167 | . . 3 ⊢ (𝐴 = +∞ → 𝐴 ∈ ℝ*) |
7 | 3, 6 | jaoi 690 | . 2 ⊢ ((𝐴 ∈ ℕ0 ∨ 𝐴 = +∞) → 𝐴 ∈ ℝ*) |
8 | 1, 7 | sylbi 120 | 1 ⊢ (𝐴 ∈ ℕ0* → 𝐴 ∈ ℝ*) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∨ wo 682 = wceq 1316 ∈ wcel 1465 +∞cpnf 7765 ℝ*cxr 7767 ℕ0cn0 8945 ℕ0*cxnn0 9008 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-io 683 ax-5 1408 ax-7 1409 ax-gen 1410 ax-ie1 1454 ax-ie2 1455 ax-8 1467 ax-10 1468 ax-11 1469 ax-i12 1470 ax-bndl 1471 ax-4 1472 ax-13 1476 ax-14 1477 ax-17 1491 ax-i9 1495 ax-ial 1499 ax-i5r 1500 ax-ext 2099 ax-sep 4016 ax-pow 4068 ax-un 4325 ax-cnex 7679 ax-resscn 7680 ax-1re 7682 ax-addrcl 7685 ax-rnegex 7697 |
This theorem depends on definitions: df-bi 116 df-tru 1319 df-nf 1422 df-sb 1721 df-clab 2104 df-cleq 2110 df-clel 2113 df-nfc 2247 df-ral 2398 df-rex 2399 df-v 2662 df-un 3045 df-in 3047 df-ss 3054 df-pw 3482 df-sn 3503 df-pr 3504 df-uni 3707 df-int 3742 df-pnf 7770 df-xr 7772 df-inn 8689 df-n0 8946 df-xnn0 9009 |
This theorem is referenced by: xnn0xrnemnf 9020 |
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