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Theorem icoun 6413
Description: The union of end-to-end closed-below, open-above real intervals. (Contributed by Paul Chapman, 15-Mar-2008.)
Assertion
Ref Expression
icoun |- (((A e. RR /\ B e. RR /\ C e. RR) /\ (A <_ B /\ B <_ C)) -> ((A[,)B) u. (B[,)C)) = (A[,)C))

Proof of Theorem icoun
StepHypRef Expression
1 breq1 2622 . . . . 5 |- (A = if(A e. RR, A, 0) -> (A <_ B <-> if(A e. RR, A, 0) <_ B))
21anbi1d 617 . . . 4 |- (A = if(A e. RR, A, 0) -> ((A <_ B /\ B <_ C) <-> (if(A e. RR, A, 0) <_ B /\ B <_ C)))
3 opreq1 3968 . . . . . 6 |- (A = if(A e. RR, A, 0) -> (A[,)B) = (if(A e. RR, A, 0)[,)B))
43uneq1d 2183 . . . . 5 |- (A = if(A e. RR, A, 0) -> ((A[,)B) u. (B[,)C)) = ((if(A e. RR, A, 0)[,)B) u. (B[,)C)))
5 opreq1 3968 . . . . 5 |- (A = if(A e. RR, A, 0) -> (A[,)C) = (if(A e. RR, A, 0)[,)C))
64, 5eqeq12d 1489 . . . 4 |- (A = if(A e. RR, A, 0) -> (((A[,)B) u. (B[,)C)) = (A[,)C) <-> ((if(A e. RR, A, 0)[,)B) u. (B[,)C)) = (if(A e. RR, A, 0)[,)C)))
72, 6imbi12d 626 . . 3 |- (A = if(A e. RR, A, 0) -> (((A <_ B /\ B <_ C) -> ((A[,)B) u. (B[,)C)) = (A[,)C)) <-> ((if(A e. RR, A, 0) <_ B /\ B <_ C) -> ((if(A e. RR, A, 0)[,)B) u. (B[,)C)) = (if(A e. RR, A, 0)[,)C))))
8 breq2 2623 . . . . 5 |- (B = if(B e. RR, B, 0) -> (if(A e. RR, A, 0) <_ B <-> if(A e. RR, A, 0) <_ if(B e. RR, B, 0)))
9 breq1 2622 . . . . 5 |- (B = if(B e. RR, B, 0) -> (B <_ C <-> if(B e. RR, B, 0) <_ C))
108, 9anbi12d 628 . . . 4 |- (B = if(B e. RR, B, 0) -> ((if(A e. RR, A, 0) <_ B /\ B <_ C) <-> (if(A e. RR, A, 0) <_ if(B e. RR, B, 0) /\ if(B e. RR, B, 0) <_ C)))
11 opreq2 3969 . . . . . 6 |- (B = if(B e. RR, B, 0) -> (if(A e. RR, A, 0)[,)B) = (if(A e. RR, A, 0)[,)if(B e. RR, B, 0)))
12 opreq1 3968 . . . . . 6 |- (B = if(B e. RR, B, 0) -> (B[,)C) = (if(B e. RR, B, 0)[,)C))
1311, 12uneq12d 2185 . . . . 5 |- (B = if(B e. RR, B, 0) -> ((if(A e. RR, A, 0)[,)B) u. (B[,)C)) = ((if(A e. RR, A, 0)[,)if(B e. RR, B, 0)) u. (if(B e. RR, B, 0)[,)C)))
1413eqeq1d 1483 . . . 4 |- (B = if(B e. RR, B, 0) -> (((if(A e. RR, A, 0)[,)B) u. (B[,)C)) = (if(A e. RR, A, 0)[,)C) <-> ((if(A e. RR, A, 0)[,)if(B e. RR, B, 0)) u. (if(B e. RR, B, 0)[,)C)) = (if(A e. RR, A, 0)[,)C)))
1510, 14imbi12d 626 . . 3 |- (B = if(B e. RR, B, 0) -> (((if(A e. RR, A, 0) <_ B /\ B <_ C) -> ((if(A e. RR, A, 0)[,)B) u. (B[,)C)) = (if(A e. RR, A, 0)[,)C)) <-> ((if(A e. RR, A, 0) <_ if(B e. RR, B, 0) /\ if(B e. RR, B, 0) <_ C) -> ((if(A e. RR, A, 0)[,)if(B e. RR, B, 0)) u. (if(B e. RR, B, 0)[,)C)) = (if(A e. RR, A, 0)[,)C))))
16 breq2 2623 . . . . 5 |- (C = if(C e. RR, C, 0) -> (if(B e. RR, B, 0) <_ C <-> if(B e. RR, B, 0) <_ if(C e. RR, C, 0)))
1716anbi2d 616 . . . 4 |- (C = if(C e. RR, C, 0) -> ((if(A e. RR, A, 0) <_ if(B e. RR, B, 0) /\ if(B e. RR, B, 0) <_ C) <-> (if(A e. RR, A, 0) <_ if(B e. RR, B, 0) /\ if(B e. RR, B, 0) <_ if(C e. RR, C, 0))))
18 opreq2 3969 . . . . . 6 |- (C = if(C e. RR, C, 0) -> (if(B e. RR, B, 0)[,)C) = (if(B e. RR, B, 0)[,)if(C e. RR, C, 0)))
1918uneq2d 2184 . . . . 5 |- (C = if(C e. RR, C, 0) -> ((if(A e. RR, A, 0)[,)if(B e. RR, B, 0)) u. (if(B e. RR, B, 0)[,)C)) = ((if(A e. RR, A, 0)[,)if(B e. RR, B, 0)) u. (if(B e. RR, B, 0)[,)if(C e. RR, C, 0))))
20 opreq2 3969 . . . . 5 |- (C = if(C e. RR, C, 0) -> (if(A e. RR, A, 0)[,)C) = (if(A e. RR, A, 0)[,)if(C e. RR, C, 0)))
2119, 20eqeq12d 1489 . . . 4 |- (C = if(C e. RR, C, 0) -> (((if(A e. RR, A, 0)[,)if(B e. RR, B, 0)) u. (if(B e. RR, B, 0)[,)C)) = (if(A e. RR, A, 0)[,)C) <-> ((if(A e. RR, A, 0)[,)if(B e. RR, B, 0)) u. (if(B e. RR, B, 0)[,)if(C e. RR, C, 0))) = (if(A e. RR, A, 0)[,)if(C e. RR, C, 0))))
2217, 21imbi12d 626 . . 3 |- (C = if(C e. RR, C, 0) -> (((if(A e. RR, A, 0) <_ if(B e. RR, B, 0) /\ if(B e. RR, B, 0) <_ C) -> ((if(A e. RR, A, 0)[,)if(B e. RR, B, 0)) u. (if(B e. RR, B, 0)[,)C)) = (if(A e. RR, A, 0)[,)C)) <-> ((if(A e. RR, A, 0) <_ if(B e. RR, B, 0) /\ if(B e. RR, B, 0) <_ if(C e. RR, C, 0)) -> ((if(A e. RR, A, 0)[,)if(B e. RR, B, 0)) u. (if(B e. RR, B, 0)[,)if(C e. RR, C, 0))) = (if(A e. RR, A, 0)[,)if(C e. RR, C, 0)))))
23 0re 5440 . . . . 5 |- 0 e. RR
2423elimel 2394 . . . 4 |- if(A e. RR, A, 0) e. RR
2523elimel 2394 . . . 4 |- if(B e. RR, B, 0) e. RR
2623elimel 2394 . . . 4 |- if(C e. RR, C, 0) e. RR
2724, 25, 26icounlem 6412 . . 3 |- ((if(A e. RR, A, 0) <_ if(B e. RR, B, 0) /\ if(B e. RR, B, 0) <_ if(C e. RR, C, 0)) -> ((if(A e. RR, A, 0)[,)if(B e. RR, B, 0)) u. (if(B e. RR, B, 0)[,)if(C e. RR, C, 0))) = (if(A e. RR, A, 0)[,)if(C e. RR, C, 0)))
287, 15, 22, 27dedth3h 2388 . 2 |- ((A e. RR /\ B e. RR /\ C e. RR) -> ((A <_ B /\ B <_ C) -> ((A[,)B) u. (B[,)C)) = (A[,)C)))
2928imp 350 1 |- (((A e. RR /\ B e. RR /\ C e. RR) /\ (A <_ B /\ B <_ C)) -> ((A[,)B) u. (B[,)C)) = (A[,)C))
Colors of variables: wff set class
Syntax hints:   -> wi 3   /\ wa 223   /\ w3a 775   = wceq 956   e. wcel 958   u. cun 2045  ifcif 2361   class class class wbr 2619  (class class class)co 3963  RRcr 5233  0cc0 5234   <_ cle 5295  [,)cico 6359
This theorem is referenced by:  efif1lem7 8736
This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7  ax-7 962  ax-gen 963  ax-8 964  ax-9 965  ax-10 966  ax-11 967  ax-12 968  ax-13 969  ax-14 970  ax-17 971  ax-4 973  ax-5o 975  ax-6o 978  ax-9o 1123  ax-10o 1140  ax-16 1210  ax-11o 1218  ax-ext 1459  ax-rep 2693  ax-sep 2703  ax-nul 2710  ax-pow 2742  ax-pr 2779  ax-un 2866  ax-inf2 4625
This theorem depends on definitions:  df-bi 147  df-or 224  df-an 225  df-3or 776  df-3an 777  df-ex 981  df-sb 1172  df-eu 1382  df-mo 1383  df-clab 1464  df-cleq 1469  df-clel 1472  df-ne 1587  df-nel 1588  df-ral 1649  df-rex 1650  df-reu 1651  df-rab 1652  df-v 1812  df-sbc 1942  df-csb 2002  df-dif 2049  df-un 2050  df-in 2051  df-ss 2053  df-pss 2055  df-nul 2281  df-if 2362  df-pw 2402  df-sn 2412  df-pr 2413  df-tp 2415  df-op 2416  df-uni 2504  df-int 2534  df-iun 2568  df-br 2620  df-opab 2667  df-tr 2681  df-eprel 2832  df-id 2835  df-po 2840  df-so 2850  df-fr 2917  df-we 2934  df-ord 2951  df-on 2952  df-lim 2953  df-suc 2954  df-om 3132  df-xp 3184  df-rel 3185  df-cnv