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Theorem icoun 6354
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 2617 . . . . 5 |- (A = if(A e. RR, A, 0) -> (A <_ B <-> if(A e. RR, A, 0) <_ B))
21anbi1d 616 . . . 4 |- (A = if(A e. RR, A, 0) -> ((A <_ B /\ B <_ C) <-> (if(A e. RR, A, 0) <_ B /\ B <_ C)))
3 opreq1 3959 . . . . . 6 |- (A = if(A e. RR, A, 0) -> (A[,)B) = (if(A e. RR, A, 0)[,)B))
43uneq1d 2179 . . . . 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 3959 . . . . 5 |- (A = if(A e. RR, A, 0) -> (A[,)C) = (if(A e. RR, A, 0)[,)C))
64, 5eqeq12d 1486 . . . 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 625 . . 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 2618 . . . . 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 2617 . . . . 5 |- (B = if(B e. RR, B, 0) -> (B <_ C <-> if(B e. RR, B, 0) <_ C))
108, 9anbi12d 627 . . . 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 3960 . . . . . 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 3959 . . . . . 6 |- (B = if(B e. RR, B, 0) -> (B[,)C) = (if(B e. RR, B, 0)[,)C))
1311, 12uneq12d 2181 . . . . 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 1480 . . . 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 625 . . 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 2618 . . . . 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 615 . . . 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 3960 . . . . . 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 2180 . . . . 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 3960 . . . . 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 1486 . . . 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 625 . . 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 5420 . . . . 5 |- 0 e. RR
2423elimel 2390 . . . 4 |- if(A e. RR, A, 0) e. RR
2523elimel 2390 . . . 4 |- if(B e. RR, B, 0) e. RR
2623elimel 2390 . . . 4 |- if(C e. RR, C, 0) e. RR
2724, 25, 26icounlem 6353 . . 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 2384 . 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 774   = wceq 954   e. wcel 956   u. cun 2041  ifcif 2357   class class class wbr 2614  (class class class)co 3954  RRcr 5213  0cc0 5214   <_ cle 5275  [,)cico 6304
This theorem is referenced by:  efif1lem7 8670
This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7  ax-7 960  ax-gen 961  ax-8 962  ax-9 963  ax-10 964  ax-11 965  ax-12 966  ax-13 967  ax-14 968  ax-17 969  ax-4 971  ax-5o 973  ax-6o 976  ax-9o 1121  ax-10o 1138  ax-16 1208  ax-11o 1216  ax-ext 1457  ax-rep 2688  ax-sep 2698  ax-nul 2705  ax-pow 2737  ax-pr 2774  ax-un 2861  ax-inf2 4605
This theorem depends on definitions:  df-bi 147  df-or 224  df-an 225  df-3or 775  df-3an 776  df-ex 979  df-sb 1170  df-eu 1380  df-mo 1381  df-clab 1462  df-cleq 1467  df-clel 1470  df-ne 1584  df-nel 1585  df-ral 1646  df-rex 1647  df-reu 1648  df-rab 1649  df-v 1808  df-sbc 1938  df-csb 1998  df-dif 2045  df-un 2046  df-in 2047  df-ss 2049  df-pss 2051  df-nul 2277  df-if 2358  df-pw 2398  df-sn 2408  df-pr 2409  df-tp 2411  df-op 2412  df-uni 2499  df-int 2529  df-iun 2563  df-br 2615  df-opab 2662  df-tr 2676  df-eprel 2827  df-id 2830  df-po 2835  df-so 2845  df-fr 2912  df-we 2929  df-ord 2946  df-on 2947  df-lim 2948  df-suc 2949  df-om 3127  df-xp 3179  df-rel 3180  df-cnv 3181  df-co