set X = (Seg 1) --> REAL;
1 in Seg 1
;
then
((Seg 1) --> REAL) . 1 = REAL
by FUNCOP_1:7;
hence
( CarProduct ((Seg 1) --> REAL) = REAL & ElmFin (((Seg 1) --> REAL),1) = REAL )
by MEASUR13:def 3, MEASUR13:def 1; ( CarProduct ((Seg 2) --> REAL) = [:REAL,REAL:] & ElmFin (((Seg 2) --> REAL),2) = REAL & CarProduct ((Seg 3) --> REAL) = [:REAL,REAL,REAL:] )
set Y = (Seg 2) --> REAL;
A1:
( 1 in Seg 2 & 2 in Seg 2 )
;
then A2:
( ((Seg 2) --> REAL) . 1 = REAL & ((Seg 2) --> REAL) . 2 = REAL )
by FUNCOP_1:7;
CarProduct ((Seg 2) --> REAL) = [:((ProdFinSeq ((Seg 2) --> REAL)) . 1),(((Seg 2) --> REAL) . (1 + 1)):]
by MEASUR13:def 3;
hence
CarProduct ((Seg 2) --> REAL) = [:REAL,REAL:]
by A2, MEASUR13:def 3; ( ElmFin (((Seg 2) --> REAL),2) = REAL & CarProduct ((Seg 3) --> REAL) = [:REAL,REAL,REAL:] )
ElmFin (((Seg 2) --> REAL),2) = ((Seg 2) --> REAL) . 2
by MEASUR13:def 1;
hence
ElmFin (((Seg 2) --> REAL),2) = REAL
by A1, FUNCOP_1:7; CarProduct ((Seg 3) --> REAL) = [:REAL,REAL,REAL:]
set Z = (Seg 3) --> REAL;
( 1 in Seg 3 & 2 in Seg 3 & 3 in Seg 3 )
;
then A3:
( ((Seg 3) --> REAL) . 1 = REAL & ((Seg 3) --> REAL) . 2 = REAL & ((Seg 3) --> REAL) . 3 = REAL )
by FUNCOP_1:7;
( (ProdFinSeq ((Seg 3) --> REAL)) . 1 = ((Seg 3) --> REAL) . 1 & (ProdFinSeq ((Seg 3) --> REAL)) . 2 = [:((ProdFinSeq ((Seg 3) --> REAL)) . 1),(((Seg 3) --> REAL) . (1 + 1)):] & (ProdFinSeq ((Seg 3) --> REAL)) . 3 = [:((ProdFinSeq ((Seg 3) --> REAL)) . 2),(((Seg 3) --> REAL) . (2 + 1)):] )
by MEASUR13:def 3;
hence
CarProduct ((Seg 3) --> REAL) = [:REAL,REAL,REAL:]
by A3, ZFMISC_1:def 3; verum