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Mirrors > Home > MPE Home > Th. List > 0g0 | Structured version Visualization version GIF version |
Description: The identity element function evaluates to the empty set on an empty structure. (Contributed by Stefan O'Rear, 2-Oct-2015.) |
Ref | Expression |
---|---|
0g0 | ⊢ ∅ = (0g‘∅) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | base0 16528 | . . 3 ⊢ ∅ = (Base‘∅) | |
2 | eqid 2798 | . . 3 ⊢ (+g‘∅) = (+g‘∅) | |
3 | eqid 2798 | . . 3 ⊢ (0g‘∅) = (0g‘∅) | |
4 | 1, 2, 3 | grpidval 17863 | . 2 ⊢ (0g‘∅) = (℩𝑒(𝑒 ∈ ∅ ∧ ∀𝑥 ∈ ∅ ((𝑒(+g‘∅)𝑥) = 𝑥 ∧ (𝑥(+g‘∅)𝑒) = 𝑥))) |
5 | noel 4247 | . . . . . 6 ⊢ ¬ 𝑒 ∈ ∅ | |
6 | 5 | intnanr 491 | . . . . 5 ⊢ ¬ (𝑒 ∈ ∅ ∧ ∀𝑥 ∈ ∅ ((𝑒(+g‘∅)𝑥) = 𝑥 ∧ (𝑥(+g‘∅)𝑒) = 𝑥)) |
7 | 6 | nex 1802 | . . . 4 ⊢ ¬ ∃𝑒(𝑒 ∈ ∅ ∧ ∀𝑥 ∈ ∅ ((𝑒(+g‘∅)𝑥) = 𝑥 ∧ (𝑥(+g‘∅)𝑒) = 𝑥)) |
8 | euex 2637 | . . . 4 ⊢ (∃!𝑒(𝑒 ∈ ∅ ∧ ∀𝑥 ∈ ∅ ((𝑒(+g‘∅)𝑥) = 𝑥 ∧ (𝑥(+g‘∅)𝑒) = 𝑥)) → ∃𝑒(𝑒 ∈ ∅ ∧ ∀𝑥 ∈ ∅ ((𝑒(+g‘∅)𝑥) = 𝑥 ∧ (𝑥(+g‘∅)𝑒) = 𝑥))) | |
9 | 7, 8 | mto 200 | . . 3 ⊢ ¬ ∃!𝑒(𝑒 ∈ ∅ ∧ ∀𝑥 ∈ ∅ ((𝑒(+g‘∅)𝑥) = 𝑥 ∧ (𝑥(+g‘∅)𝑒) = 𝑥)) |
10 | iotanul 6302 | . . 3 ⊢ (¬ ∃!𝑒(𝑒 ∈ ∅ ∧ ∀𝑥 ∈ ∅ ((𝑒(+g‘∅)𝑥) = 𝑥 ∧ (𝑥(+g‘∅)𝑒) = 𝑥)) → (℩𝑒(𝑒 ∈ ∅ ∧ ∀𝑥 ∈ ∅ ((𝑒(+g‘∅)𝑥) = 𝑥 ∧ (𝑥(+g‘∅)𝑒) = 𝑥))) = ∅) | |
11 | 9, 10 | ax-mp 5 | . 2 ⊢ (℩𝑒(𝑒 ∈ ∅ ∧ ∀𝑥 ∈ ∅ ((𝑒(+g‘∅)𝑥) = 𝑥 ∧ (𝑥(+g‘∅)𝑒) = 𝑥))) = ∅ |
12 | 4, 11 | eqtr2i 2822 | 1 ⊢ ∅ = (0g‘∅) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 ∧ wa 399 = wceq 1538 ∃wex 1781 ∈ wcel 2111 ∃!weu 2628 ∀wral 3106 ∅c0 4243 ℩cio 6281 ‘cfv 6324 (class class class)co 7135 +gcplusg 16557 0gc0g 16705 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1911 ax-6 1970 ax-7 2015 ax-8 2113 ax-9 2121 ax-10 2142 ax-11 2158 ax-12 2175 ax-ext 2770 ax-sep 5167 ax-nul 5174 ax-pow 5231 ax-pr 5295 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 845 df-3an 1086 df-tru 1541 df-ex 1782 df-nf 1786 df-sb 2070 df-mo 2598 df-eu 2629 df-clab 2777 df-cleq 2791 df-clel 2870 df-nfc 2938 df-ral 3111 df-rex 3112 df-v 3443 df-sbc 3721 df-dif 3884 df-un 3886 df-in 3888 df-ss 3898 df-nul 4244 df-if 4426 df-sn 4526 df-pr 4528 df-op 4532 df-uni 4801 df-br 5031 df-opab 5093 df-mpt 5111 df-id 5425 df-xp 5525 df-rel 5526 df-cnv 5527 df-co 5528 df-dm 5529 df-iota 6283 df-fun 6326 df-fv 6332 df-ov 7138 df-slot 16479 df-base 16481 df-0g 16707 |
This theorem is referenced by: frmd0 18017 ringidval 19246 |
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