Theorem foco 5280

Description: Composition of onto functions. (Contributed by set.mm contributors, 22-Mar-2006.)

Assertion

Ref	Expression
foco	⊢ ((F:B–onto→C ∧ G:A–onto→B) → (F ∘ G):A–onto→C)

Proof of Theorem foco

Step	Hyp	Ref	Expression
1		fco 5232	. . . 4 ⊢ ((F:B–→C ∧ G:A–→B) → (F ∘ G):A–→C)
2	1	ad2ant2r 727	. . 3 ⊢ (((F:B–→C ∧ ran F = C) ∧ (G:A–→B ∧ ran G = B)) → (F ∘ G):A–→C)
3		fdm 5227	. . . . . . 7 ⊢ (F:B–→C → dom F = B)
4		eqtr3 2372	. . . . . . 7 ⊢ ((dom F = B ∧ ran G = B) → dom F = ran G)
5	3, 4	sylan 457	. . . . . 6 ⊢ ((F:B–→C ∧ ran G = B) → dom F = ran G)
6		rncoeq 4976	. . . . . . . 8 ⊢ (dom F = ran G → ran (F ∘ G) = ran F)
7	6	eqeq1d 2361	. . . . . . 7 ⊢ (dom F = ran G → (ran (F ∘ G) = C ↔ ran F = C))
8	7	biimpar 471	. . . . . 6 ⊢ ((dom F = ran G ∧ ran F = C) → ran (F ∘ G) = C)
9	5, 8	sylan 457	. . . . 5 ⊢ (((F:B–→C ∧ ran G = B) ∧ ran F = C) → ran (F ∘ G) = C)
10	9	an32s 779	. . . 4 ⊢ (((F:B–→C ∧ ran F = C) ∧ ran G = B) → ran (F ∘ G) = C)
11	10	adantrl 696	. . 3 ⊢ (((F:B–→C ∧ ran F = C) ∧ (G:A–→B ∧ ran G = B)) → ran (F ∘ G) = C)
12	2, 11	jca 518	. 2 ⊢ (((F:B–→C ∧ ran F = C) ∧ (G:A–→B ∧ ran G = B)) → ((F ∘ G):A–→C ∧ ran (F ∘ G) = C))
13		dffo2 5274	. . 3 ⊢ (F:B–onto→C ↔ (F:B–→C ∧ ran F = C))
14		dffo2 5274	. . 3 ⊢ (G:A–onto→B ↔ (G:A–→B ∧ ran G = B))
15	13, 14	anbi12i 678	. 2 ⊢ ((F:B–onto→C ∧ G:A–onto→B) ↔ ((F:B–→C ∧ ran F = C) ∧ (G:A–→B ∧ ran G = B)))
16		dffo2 5274	. 2 ⊢ ((F ∘ G):A–onto→C ↔ ((F ∘ G):A–→C ∧ ran (F ∘ G) = C))
17	12, 15, 16	3imtr4i 257	1 ⊢ ((F:B–onto→C ∧ G:A–onto→B) → (F ∘ G):A–onto→C)

Syntax hints:   → wi 4   ∧ wa 358   = wceq 1642   ∘ ccom 4722  dom cdm 4773  ran crn 4774  –→wf 4778  –onto→wfo 4780

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-13 1712  ax-14 1714  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334  ax-nin 4079  ax-xp 4080  ax-cnv 4081  ax-1c 4082  ax-sset 4083  ax-si 4084  ax-ins2 4085  ax-ins3 4086  ax-typlower 4087  ax-sn 4088

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3or 935  df-3an 936  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-eu 2208  df-mo 2209  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2479  df-ne 2519  df-ral 2620  df-rex 2621  df-reu 2622  df-rmo 2623  df-rab 2624  df-v 2862  df-sbc 3048  df-nin 3212  df-compl 3213  df-in 3214  df-un 3215  df-dif 3216  df-symdif 3217  df-ss 3260  df-pss 3262  df-nul 3552  df-if 3664  df-pw 3725  df-sn 3742  df-pr 3743  df-uni 3893  df-int 3928  df-opk 4059  df-1c 4137  df-pw1 4138  df-uni1 4139  df-xpk 4186  df-cnvk 4187  df-ins2k 4188  df-ins3k 4189  df-imak 4190  df-cok 4191  df-p6 4192  df-sik 4193  df-ssetk 4194  df-imagek 4195  df-idk 4196  df-iota 4340  df-0c 4378  df-addc 4379  df-nnc 4380  df-fin 4381  df-lefin 4441  df-ltfin 4442  df-ncfin 4443  df-tfin 4444  df-evenfin 4445  df-oddfin 4446  df-sfin 4447  df-spfin 4448  df-phi 4566  df-op 4567  df-proj1 4568  df-proj2 4569  df-opab 4624  df-br 4641  df-co 4727  df-ima 4728  df-id 4768  df-cnv 4786  df-rn 4787  df-dm 4788  df-fun 4790  df-fn 4791  df-f 4792  df-fo 4794

This theorem is referenced by:  f1oco  5309