Theorem dmcoeq 2573

Description: Domain of a composition.

Assertion

Ref	Expression
dmcoeq	|- (dom A = ran B -> dom (A o. B) = dom B)

Proof of Theorem dmcoeq

Step	Hyp	Ref	Expression
1		eqimss2 1549	. 2 |- (dom A = ran B -> ran B (_ dom A)
2		dmcosseq 2572	. 2 |- (ran B (_ dom A -> dom (A o. B) = dom B)
3	1, 2	syl 12	1 |- (dom A = ran B -> dom (A o. B) = dom B)

Syntax hints:   -> wi 2   = wceq 1091   (_ wss 1487  dom cdm 2410  ran crn 2411   o. ccom 2414

This theorem is referenced by:  rncoeq 2574  f1oco 2816  f1ococnv2 2817

This theorem was proved from axioms:  ax-1 3  ax-2 4  ax-3 5  ax-mp 6  ax-4 673  ax-5 674  ax-6 675  ax-7 676  ax-gen 677  ax-8 798  ax-9 799  ax-10 800  ax-11 801  ax-12 802  ax-13 804  ax-14 805  ax-16 922  ax-17 925  ax-ext 1074  ax-rep 1075  ax-pow 1077

This theorem depends on definitions:  df-bi 128  df-or 197  df-an 198  df-ex 679  df-sb 853  df-clab 1093  df-cleq 1097  df-clel 1099  df-v 1349  df-dif 1489  df-un 1490  df-in 1491  df-ss 1492  df-nul 1708  df-pw 1799  df-sn 1811  df-pr 1812  df-op 1815  df-br 2063  df-opab 2098  df-cnv 2426  df-co 2427  df-dm 2428  df-rn 2429

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