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Mirrors > Home > MPE Home > Th. List > nsuceq0 | Structured version Visualization version GIF version |
Description: No successor is empty. (Contributed by NM, 3-Apr-1995.) |
Ref | Expression |
---|---|
nsuceq0 | ⊢ suc 𝐴 ≠ ∅ |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | noel 4296 | . . . 4 ⊢ ¬ 𝐴 ∈ ∅ | |
2 | sucidg 6269 | . . . . 5 ⊢ (𝐴 ∈ V → 𝐴 ∈ suc 𝐴) | |
3 | eleq2 2901 | . . . . 5 ⊢ (suc 𝐴 = ∅ → (𝐴 ∈ suc 𝐴 ↔ 𝐴 ∈ ∅)) | |
4 | 2, 3 | syl5ibcom 247 | . . . 4 ⊢ (𝐴 ∈ V → (suc 𝐴 = ∅ → 𝐴 ∈ ∅)) |
5 | 1, 4 | mtoi 201 | . . 3 ⊢ (𝐴 ∈ V → ¬ suc 𝐴 = ∅) |
6 | 0ex 5211 | . . . . . 6 ⊢ ∅ ∈ V | |
7 | eleq1 2900 | . . . . . 6 ⊢ (𝐴 = ∅ → (𝐴 ∈ V ↔ ∅ ∈ V)) | |
8 | 6, 7 | mpbiri 260 | . . . . 5 ⊢ (𝐴 = ∅ → 𝐴 ∈ V) |
9 | 8 | con3i 157 | . . . 4 ⊢ (¬ 𝐴 ∈ V → ¬ 𝐴 = ∅) |
10 | sucprc 6266 | . . . . 5 ⊢ (¬ 𝐴 ∈ V → suc 𝐴 = 𝐴) | |
11 | 10 | eqeq1d 2823 | . . . 4 ⊢ (¬ 𝐴 ∈ V → (suc 𝐴 = ∅ ↔ 𝐴 = ∅)) |
12 | 9, 11 | mtbird 327 | . . 3 ⊢ (¬ 𝐴 ∈ V → ¬ suc 𝐴 = ∅) |
13 | 5, 12 | pm2.61i 184 | . 2 ⊢ ¬ suc 𝐴 = ∅ |
14 | 13 | neir 3019 | 1 ⊢ suc 𝐴 ≠ ∅ |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 = wceq 1537 ∈ wcel 2114 ≠ wne 3016 Vcvv 3494 ∅c0 4291 suc csuc 6193 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1911 ax-6 1970 ax-7 2015 ax-8 2116 ax-9 2124 ax-10 2145 ax-11 2161 ax-12 2177 ax-ext 2793 ax-nul 5210 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-tru 1540 df-ex 1781 df-nf 1785 df-sb 2070 df-clab 2800 df-cleq 2814 df-clel 2893 df-nfc 2963 df-ne 3017 df-v 3496 df-dif 3939 df-un 3941 df-nul 4292 df-sn 4568 df-suc 6197 |
This theorem is referenced by: 0elsuc 7550 peano3 7603 2on0 8113 oelim2 8221 limenpsi 8692 enp1i 8753 findcard2 8758 fseqdom 9452 dfac12lem2 9570 cfsuc 9679 cfpwsdom 10006 rankcf 10199 dfrdg2 33040 nosgnn0 33165 sltsolem1 33180 dfrdg4 33412 dfsucon 39909 ensucne0 39915 ensucne0OLD 39916 |
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