Metamath Proof Explorer |
< Previous
Next >
Nearby theorems |
||
Mirrors > Home > MPE Home > Th. List > equid | Structured version Visualization version GIF version |
Description: Identity law for equality. Lemma 2 of [KalishMontague] p. 85. See also Lemma 6 of [Tarski] p. 68. (Contributed by NM, 1-Apr-2005.) (Revised by NM, 9-Apr-2017.) (Proof shortened by Wolf Lammen, 5-Feb-2018.) (Proof shortened by Wolf Lammen, 22-Aug-2020.) |
Ref | Expression |
---|---|
equid | ⊢ 𝑥 = 𝑥 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ax7v1 1924 | . . 3 ⊢ (𝑦 = 𝑥 → (𝑦 = 𝑥 → 𝑥 = 𝑥)) | |
2 | 1 | pm2.43i 50 | . 2 ⊢ (𝑦 = 𝑥 → 𝑥 = 𝑥) |
3 | ax6ev 1877 | . 2 ⊢ ∃𝑦 𝑦 = 𝑥 | |
4 | 2, 3 | exlimiiv 1846 | 1 ⊢ 𝑥 = 𝑥 |
Colors of variables: wff setvar class |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1713 ax-4 1728 ax-5 1827 ax-6 1875 ax-7 1922 |
This theorem depends on definitions: df-bi 196 df-ex 1696 |
This theorem is referenced by: nfequid 1927 equcomiv 1928 equcomi 1931 stdpc6 1944 ax6dgen 1992 ax13dgen1 2001 ax13dgen3 2003 sbid 2100 exists1 2549 vjust 3174 vex 3176 reu6 3362 nfccdeq 3400 sbc8g 3410 dfnul3 3877 rab0OLD 3910 int0OLD 4426 dfid3 4954 isso2i 4991 relop 5194 f1eqcocnv 6456 fsplit 7169 mpt2xopoveq 7232 ruv 8390 dfac2 8836 konigthlem 9269 hash2prde 13109 hashge2el2difr 13118 pospo 16796 mamulid 20066 mdetdiagid 20225 alexsubALTlem3 21663 trust 21843 isppw2 24641 xmstrkgc 25566 nbgranself 25963 usgrasscusgra 26011 rusgrasn 26472 avril1 26711 foo3 28686 domep 30942 wlimeq12 31009 bj-ssbid2 31834 bj-ssbid1 31836 bj-vjust 31974 mptsnunlem 32361 ax12eq 33244 elnev 37661 ipo0 37674 ifr0 37675 tratrb 37767 tratrbVD 38119 unirnmapsn 38401 hspmbl 39519 |
Copyright terms: Public domain | W3C validator |