let r be Real; for X being real-membered set holds multRel (X,r) = ((curry multreal) . r) |_2 X
let X be real-membered set ; multRel (X,r) = ((curry multreal) . r) |_2 X
set g = (curry multreal) . r;
now for x, y being object holds
( ( [x,y] in multRel (X,r) implies [x,y] in ((curry multreal) . r) |_2 X ) & ( [x,y] in ((curry multreal) . r) |_2 X implies [x,y] in multRel (X,r) ) )let x,
y be
object ;
( ( [x,y] in multRel (X,r) implies [x,y] in ((curry multreal) . r) |_2 X ) & ( [x,y] in ((curry multreal) . r) |_2 X implies [x,y] in multRel (X,r) ) )reconsider a =
x,
b =
y as
set by TARSKI:1;
hereby ( [x,y] in ((curry multreal) . r) |_2 X implies [x,y] in multRel (X,r) )
assume A1:
[x,y] in multRel (
X,
r)
;
[x,y] in ((curry multreal) . r) |_2 Xthen
[a,b] in multRel (
X,
r)
;
then
(
a in X &
b in X )
by MMLQUER2:4;
then reconsider a =
a,
b =
b as
Real ;
[a,b] in multRel (
X,
r)
by A1;
then A2:
(
a in X &
b in X &
b = r * a )
by Th42;
(
r in REAL &
a in REAL )
by XREAL_0:def 1;
then
[r,a] in [:REAL,REAL:]
by ZFMISC_1:87;
then A3:
[r,a] in dom multreal
by FUNCT_2:def 1;
A4:
b =
multreal . (
r,
a)
by A2, BINOP_2:def 11
.=
((curry multreal) . r) . a
by A3, FUNCT_5:20
;
a in dom ((curry multreal) . r)
by A3, FUNCT_5:20;
hence
[x,y] in ((curry multreal) . r) |_2 X
by A2, A4, FUNCT_1:1, MMLQUER2:4;
verum
end; assume
[x,y] in ((curry multreal) . r) |_2 X
;
[x,y] in multRel (X,r)then
[a,b] in ((curry multreal) . r) |_2 X
;
then A5:
(
a in X &
b in X &
[a,b] in (curry multreal) . r )
by MMLQUER2:4;
then reconsider a =
a,
b =
b as
Real ;
(
r in REAL &
a in REAL )
by XREAL_0:def 1;
then
[r,a] in [:REAL,REAL:]
by ZFMISC_1:87;
then A6:
[r,a] in dom multreal
by FUNCT_2:def 1;
(
a in dom ((curry multreal) . r) &
((curry multreal) . r) . a = b )
by A5, FUNCT_1:1;
then b =
multreal . (
r,
a)
by A6, FUNCT_5:20
.=
r * a
by BINOP_2:def 11
;
hence
[x,y] in multRel (
X,
r)
by A5, Th42;
verum end;
hence
multRel (X,r) = ((curry multreal) . r) |_2 X
by RELAT_1:def 2; verum