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Mirrors > Home > MPE Home > Th. List > sdom1 | Structured version Visualization version GIF version |
Description: A set has less than one member iff it is empty. (Contributed by Stefan O'Rear, 28-Oct-2014.) |
Ref | Expression |
---|---|
sdom1 | ⊢ (𝐴 ≺ 1𝑜 ↔ 𝐴 = ∅) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | domnsym 8086 | . . . . 5 ⊢ (1𝑜 ≼ 𝐴 → ¬ 𝐴 ≺ 1𝑜) | |
2 | 1 | con2i 134 | . . . 4 ⊢ (𝐴 ≺ 1𝑜 → ¬ 1𝑜 ≼ 𝐴) |
3 | 0sdom1dom 8158 | . . . 4 ⊢ (∅ ≺ 𝐴 ↔ 1𝑜 ≼ 𝐴) | |
4 | 2, 3 | sylnibr 319 | . . 3 ⊢ (𝐴 ≺ 1𝑜 → ¬ ∅ ≺ 𝐴) |
5 | relsdom 7962 | . . . . 5 ⊢ Rel ≺ | |
6 | 5 | brrelexi 5158 | . . . 4 ⊢ (𝐴 ≺ 1𝑜 → 𝐴 ∈ V) |
7 | 0sdomg 8089 | . . . . 5 ⊢ (𝐴 ∈ V → (∅ ≺ 𝐴 ↔ 𝐴 ≠ ∅)) | |
8 | 7 | necon2bbid 2837 | . . . 4 ⊢ (𝐴 ∈ V → (𝐴 = ∅ ↔ ¬ ∅ ≺ 𝐴)) |
9 | 6, 8 | syl 17 | . . 3 ⊢ (𝐴 ≺ 1𝑜 → (𝐴 = ∅ ↔ ¬ ∅ ≺ 𝐴)) |
10 | 4, 9 | mpbird 247 | . 2 ⊢ (𝐴 ≺ 1𝑜 → 𝐴 = ∅) |
11 | 1n0 7575 | . . . 4 ⊢ 1𝑜 ≠ ∅ | |
12 | 1on 7567 | . . . . . 6 ⊢ 1𝑜 ∈ On | |
13 | 12 | elexi 3213 | . . . . 5 ⊢ 1𝑜 ∈ V |
14 | 13 | 0sdom 8091 | . . . 4 ⊢ (∅ ≺ 1𝑜 ↔ 1𝑜 ≠ ∅) |
15 | 11, 14 | mpbir 221 | . . 3 ⊢ ∅ ≺ 1𝑜 |
16 | breq1 4656 | . . 3 ⊢ (𝐴 = ∅ → (𝐴 ≺ 1𝑜 ↔ ∅ ≺ 1𝑜)) | |
17 | 15, 16 | mpbiri 248 | . 2 ⊢ (𝐴 = ∅ → 𝐴 ≺ 1𝑜) |
18 | 10, 17 | impbii 199 | 1 ⊢ (𝐴 ≺ 1𝑜 ↔ 𝐴 = ∅) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 ↔ wb 196 = wceq 1483 ∈ wcel 1990 ≠ wne 2794 Vcvv 3200 ∅c0 3915 class class class wbr 4653 Oncon0 5723 1𝑜c1o 7553 ≼ cdom 7953 ≺ csdm 7954 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1722 ax-4 1737 ax-5 1839 ax-6 1888 ax-7 1935 ax-8 1992 ax-9 1999 ax-10 2019 ax-11 2034 ax-12 2047 ax-13 2246 ax-ext 2602 ax-sep 4781 ax-nul 4789 ax-pow 4843 ax-pr 4906 ax-un 6949 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-3or 1038 df-3an 1039 df-tru 1486 df-ex 1705 df-nf 1710 df-sb 1881 df-eu 2474 df-mo 2475 df-clab 2609 df-cleq 2615 df-clel 2618 df-nfc 2753 df-ne 2795 df-ral 2917 df-rex 2918 df-rab 2921 df-v 3202 df-sbc 3436 df-dif 3577 df-un 3579 df-in 3581 df-ss 3588 df-pss 3590 df-nul 3916 df-if 4087 df-pw 4160 df-sn 4178 df-pr 4180 df-tp 4182 df-op 4184 df-uni 4437 df-br 4654 df-opab 4713 df-tr 4753 df-id 5024 df-eprel 5029 df-po 5035 df-so 5036 df-fr 5073 df-we 5075 df-xp 5120 df-rel 5121 df-cnv 5122 df-co 5123 df-dm 5124 df-rn 5125 df-res 5126 df-ima 5127 df-ord 5726 df-on 5727 df-lim 5728 df-suc 5729 df-iota 5851 df-fun 5890 df-fn 5891 df-f 5892 df-f1 5893 df-fo 5894 df-f1o 5895 df-fv 5896 df-om 7066 df-1o 7560 df-er 7742 df-en 7956 df-dom 7957 df-sdom 7958 |
This theorem is referenced by: modom 8161 frgpcyg 19922 |
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