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Mirrors > Home > MPE Home > Th. List > omsucne | Structured version Visualization version GIF version |
Description: A natural number is not the successor of itself. (Contributed by AV, 17-Oct-2023.) |
Ref | Expression |
---|---|
omsucne | ⊢ (𝐴 ∈ ω → 𝐴 ≠ suc 𝐴) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nnord 7895 | . . . . 5 ⊢ (𝐴 ∈ ω → Ord 𝐴) | |
2 | orddisj 6424 | . . . . 5 ⊢ (Ord 𝐴 → (𝐴 ∩ {𝐴}) = ∅) | |
3 | 1, 2 | syl 17 | . . . 4 ⊢ (𝐴 ∈ ω → (𝐴 ∩ {𝐴}) = ∅) |
4 | snnzg 4779 | . . . 4 ⊢ (𝐴 ∈ ω → {𝐴} ≠ ∅) | |
5 | disjpss 4467 | . . . 4 ⊢ (((𝐴 ∩ {𝐴}) = ∅ ∧ {𝐴} ≠ ∅) → 𝐴 ⊊ (𝐴 ∪ {𝐴})) | |
6 | 3, 4, 5 | syl2anc 584 | . . 3 ⊢ (𝐴 ∈ ω → 𝐴 ⊊ (𝐴 ∪ {𝐴})) |
7 | 6 | pssned 4111 | . 2 ⊢ (𝐴 ∈ ω → 𝐴 ≠ (𝐴 ∪ {𝐴})) |
8 | df-suc 6392 | . . 3 ⊢ suc 𝐴 = (𝐴 ∪ {𝐴}) | |
9 | 8 | neeq2i 3004 | . 2 ⊢ (𝐴 ≠ suc 𝐴 ↔ 𝐴 ≠ (𝐴 ∪ {𝐴})) |
10 | 7, 9 | sylibr 234 | 1 ⊢ (𝐴 ∈ ω → 𝐴 ≠ suc 𝐴) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 = wceq 1537 ∈ wcel 2106 ≠ wne 2938 ∪ cun 3961 ∩ cin 3962 ⊊ wpss 3964 ∅c0 4339 {csn 4631 Ord word 6385 suc csuc 6388 ωcom 7887 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1908 ax-6 1965 ax-7 2005 ax-8 2108 ax-9 2116 ax-ext 2706 ax-sep 5302 ax-nul 5312 ax-pr 5438 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3an 1088 df-tru 1540 df-fal 1550 df-ex 1777 df-sb 2063 df-clab 2713 df-cleq 2727 df-clel 2814 df-ne 2939 df-ral 3060 df-rex 3069 df-rab 3434 df-v 3480 df-dif 3966 df-un 3968 df-in 3970 df-ss 3980 df-pss 3983 df-nul 4340 df-if 4532 df-pw 4607 df-sn 4632 df-pr 4634 df-op 4638 df-uni 4913 df-br 5149 df-opab 5211 df-tr 5266 df-eprel 5589 df-po 5597 df-so 5598 df-fr 5641 df-we 5643 df-ord 6389 df-on 6390 df-suc 6392 df-om 7888 |
This theorem is referenced by: 1one2o 8683 |
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