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Mirrors > Home > MPE Home > Th. List > ondif1 | Structured version Visualization version GIF version |
Description: Two ways to say that 𝐴 is a nonzero ordinal number. Lemma 1.10 of [Schloeder] p. 2. (Contributed by Mario Carneiro, 21-May-2015.) |
Ref | Expression |
---|---|
ondif1 | ⊢ (𝐴 ∈ (On ∖ 1o) ↔ (𝐴 ∈ On ∧ ∅ ∈ 𝐴)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dif1o 8530 | . 2 ⊢ (𝐴 ∈ (On ∖ 1o) ↔ (𝐴 ∈ On ∧ 𝐴 ≠ ∅)) | |
2 | on0eln0 6432 | . . 3 ⊢ (𝐴 ∈ On → (∅ ∈ 𝐴 ↔ 𝐴 ≠ ∅)) | |
3 | 2 | pm5.32i 573 | . 2 ⊢ ((𝐴 ∈ On ∧ ∅ ∈ 𝐴) ↔ (𝐴 ∈ On ∧ 𝐴 ≠ ∅)) |
4 | 1, 3 | bitr4i 277 | 1 ⊢ (𝐴 ∈ (On ∖ 1o) ↔ (𝐴 ∈ On ∧ ∅ ∈ 𝐴)) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 205 ∧ wa 394 ∈ wcel 2099 ≠ wne 2930 ∖ cdif 3944 ∅c0 4325 Oncon0 6376 1oc1o 8489 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1790 ax-4 1804 ax-5 1906 ax-6 1964 ax-7 2004 ax-8 2101 ax-9 2109 ax-ext 2697 ax-sep 5304 ax-nul 5311 ax-pr 5433 |
This theorem depends on definitions: df-bi 206 df-an 395 df-or 846 df-3or 1085 df-3an 1086 df-tru 1537 df-fal 1547 df-ex 1775 df-sb 2061 df-clab 2704 df-cleq 2718 df-clel 2803 df-ne 2931 df-ral 3052 df-rex 3061 df-rab 3420 df-v 3464 df-dif 3950 df-un 3952 df-in 3954 df-ss 3964 df-pss 3967 df-nul 4326 df-if 4534 df-pw 4609 df-sn 4634 df-pr 4636 df-op 4640 df-uni 4914 df-br 5154 df-opab 5216 df-tr 5271 df-eprel 5586 df-po 5594 df-so 5595 df-fr 5637 df-we 5639 df-ord 6379 df-on 6380 df-suc 6382 df-1o 8496 |
This theorem is referenced by: cantnflem2 9733 oef1o 9741 cnfcom3 9747 infxpenc 10061 onexoegt 42909 ondif1i 42928 omnord1 42971 oenord1 42982 cantnftermord 42986 succlg 42994 dflim5 42995 onmcl 42997 omabs2 42998 naddwordnexlem4 43068 |
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