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Theorem cnco 21867
Description: The composition of two continuous functions is a continuous function. (Contributed by FL, 8-Dec-2006.) (Revised by Mario Carneiro, 21-Aug-2015.)
Assertion
Ref Expression
cnco ((𝐹 ∈ (𝐽 Cn 𝐾) ∧ 𝐺 ∈ (𝐾 Cn 𝐿)) → (𝐺𝐹) ∈ (𝐽 Cn 𝐿))

Proof of Theorem cnco
Dummy variable 𝑥 is distinct from all other variables.
StepHypRef Expression
1 cntop1 21841 . . 3 (𝐹 ∈ (𝐽 Cn 𝐾) → 𝐽 ∈ Top)
2 cntop2 21842 . . 3 (𝐺 ∈ (𝐾 Cn 𝐿) → 𝐿 ∈ Top)
31, 2anim12i 615 . 2 ((𝐹 ∈ (𝐽 Cn 𝐾) ∧ 𝐺 ∈ (𝐾 Cn 𝐿)) → (𝐽 ∈ Top ∧ 𝐿 ∈ Top))
4 eqid 2824 . . . . 5 𝐾 = 𝐾
5 eqid 2824 . . . . 5 𝐿 = 𝐿
64, 5cnf 21847 . . . 4 (𝐺 ∈ (𝐾 Cn 𝐿) → 𝐺: 𝐾 𝐿)
7 eqid 2824 . . . . 5 𝐽 = 𝐽
87, 4cnf 21847 . . . 4 (𝐹 ∈ (𝐽 Cn 𝐾) → 𝐹: 𝐽 𝐾)
9 fco 6519 . . . 4 ((𝐺: 𝐾 𝐿𝐹: 𝐽 𝐾) → (𝐺𝐹): 𝐽 𝐿)
106, 8, 9syl2anr 599 . . 3 ((𝐹 ∈ (𝐽 Cn 𝐾) ∧ 𝐺 ∈ (𝐾 Cn 𝐿)) → (𝐺𝐹): 𝐽 𝐿)
11 cnvco 5743 . . . . . . 7 (𝐺𝐹) = (𝐹𝐺)
1211imaeq1i 5913 . . . . . 6 ((𝐺𝐹) “ 𝑥) = ((𝐹𝐺) “ 𝑥)
13 imaco 6091 . . . . . 6 ((𝐹𝐺) “ 𝑥) = (𝐹 “ (𝐺𝑥))
1412, 13eqtri 2847 . . . . 5 ((𝐺𝐹) “ 𝑥) = (𝐹 “ (𝐺𝑥))
15 simpll 766 . . . . . 6 (((𝐹 ∈ (𝐽 Cn 𝐾) ∧ 𝐺 ∈ (𝐾 Cn 𝐿)) ∧ 𝑥𝐿) → 𝐹 ∈ (𝐽 Cn 𝐾))
16 cnima 21866 . . . . . . 7 ((𝐺 ∈ (𝐾 Cn 𝐿) ∧ 𝑥𝐿) → (𝐺𝑥) ∈ 𝐾)
1716adantll 713 . . . . . 6 (((𝐹 ∈ (𝐽 Cn 𝐾) ∧ 𝐺 ∈ (𝐾 Cn 𝐿)) ∧ 𝑥𝐿) → (𝐺𝑥) ∈ 𝐾)
18 cnima 21866 . . . . . 6 ((𝐹 ∈ (𝐽 Cn 𝐾) ∧ (𝐺𝑥) ∈ 𝐾) → (𝐹 “ (𝐺𝑥)) ∈ 𝐽)
1915, 17, 18syl2anc 587 . . . . 5 (((𝐹 ∈ (𝐽 Cn 𝐾) ∧ 𝐺 ∈ (𝐾 Cn 𝐿)) ∧ 𝑥𝐿) → (𝐹 “ (𝐺𝑥)) ∈ 𝐽)
2014, 19eqeltrid 2920 . . . 4 (((𝐹 ∈ (𝐽 Cn 𝐾) ∧ 𝐺 ∈ (𝐾 Cn 𝐿)) ∧ 𝑥𝐿) → ((𝐺𝐹) “ 𝑥) ∈ 𝐽)
2120ralrimiva 3177 . . 3 ((𝐹 ∈ (𝐽 Cn 𝐾) ∧ 𝐺 ∈ (𝐾 Cn 𝐿)) → ∀𝑥𝐿 ((𝐺𝐹) “ 𝑥) ∈ 𝐽)
2210, 21jca 515 . 2 ((𝐹 ∈ (𝐽 Cn 𝐾) ∧ 𝐺 ∈ (𝐾 Cn 𝐿)) → ((𝐺𝐹): 𝐽 𝐿 ∧ ∀𝑥𝐿 ((𝐺𝐹) “ 𝑥) ∈ 𝐽))
237, 5iscn2 21839 . 2 ((𝐺𝐹) ∈ (𝐽 Cn 𝐿) ↔ ((𝐽 ∈ Top ∧ 𝐿 ∈ Top) ∧ ((𝐺𝐹): 𝐽 𝐿 ∧ ∀𝑥𝐿 ((𝐺𝐹) “ 𝑥) ∈ 𝐽)))
243, 22, 23sylanbrc 586 1 ((𝐹 ∈ (𝐽 Cn 𝐾) ∧ 𝐺 ∈ (𝐾 Cn 𝐿)) → (𝐺𝐹) ∈ (𝐽 Cn 𝐿))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wa 399  wcel 2115  wral 3133   cuni 4824  ccnv 5541  cima 5545  ccom 5546  wf 6339  (class class class)co 7145  Topctop 21494   Cn ccn 21825
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 1912  ax-6 1971  ax-7 2016  ax-8 2117  ax-9 2125  ax-10 2146  ax-11 2162  ax-12 2179  ax-ext 2796  ax-sep 5189  ax-nul 5196  ax-pow 5253  ax-pr 5317  ax-un 7451
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 2071  df-mo 2624  df-eu 2655  df-clab 2803  df-cleq 2817  df-clel 2896  df-nfc 2964  df-ral 3138  df-rex 3139  df-rab 3142  df-v 3482  df-sbc 3759  df-dif 3922  df-un 3924  df-in 3926  df-ss 3936  df-nul 4276  df-if 4450  df-pw 4523  df-sn 4550  df-pr 4552  df-op 4556  df-uni 4825  df-br 5053  df-opab 5115  df-mpt 5133  df-id 5447  df-xp 5548  df-rel 5549  df-cnv 5550  df-co 5551  df-dm 5552  df-rn 5553  df-res 5554  df-ima 5555  df-iota 6302  df-fun 6345  df-fn 6346  df-f 6347  df-fv 6351  df-ov 7148  df-oprab 7149  df-mpo 7150  df-map 8398  df-top 21495  df-topon 21512  df-cn 21828
This theorem is referenced by:  kgencn2  22158  txcn  22227  xkoco1cn  22258  xkoco2cn  22259  xkococnlem  22260  xkococn  22261  cnmpt11  22264  cnmpt21  22272  hmeoco  22373  qtophmeo  22418  htpyco1  23579  htpyco2  23580  phtpyco2  23591  reparphti  23598  reparpht  23599  phtpcco2  23600  copco  23619  pi1cof  23660  pi1coghm  23662  cnpconn  32502  txsconnlem  32512  txsconn  32513  cvmlift3lem2  32592  cvmlift3lem4  32594  cvmlift3lem5  32595  cvmlift3lem6  32596  hausgraph  40009
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