let a be Real; for t being 1 _greater Nat ex x1, x2 being object st
( x1 in dom (F_dp1 (t,a)) & x2 in dom (F_dp1 (t,a)) & x1 <> x2 & (F_dp1 (t,a)) . x1 = (F_dp1 (t,a)) . x2 )
let t be 1 _greater Nat; ex x1, x2 being object st
( x1 in dom (F_dp1 (t,a)) & x2 in dom (F_dp1 (t,a)) & x1 <> x2 & (F_dp1 (t,a)) . x1 = (F_dp1 (t,a)) . x2 )
set A = dom (F_dp1 (t,a));
set B = rng (F_dp1 (t,a));
A1:
( card (rng (F_dp1 (t,a))) in card (dom (F_dp1 (t,a))) & rng (F_dp1 (t,a)) <> {} )
by Lm10;
defpred S1[ object , object ] means ex m1 being object st
( $1 in dom (F_dp1 (t,a)) & $2 = m1 & (F_dp1 (t,a)) . $1 = m1 );
A2:
for x being object st x in dom (F_dp1 (t,a)) holds
ex y being object st
( y in rng (F_dp1 (t,a)) & S1[x,y] )
by FUNCT_1:3;
consider h being Function of (dom (F_dp1 (t,a))),(rng (F_dp1 (t,a))) such that
A3:
for x being object st x in dom (F_dp1 (t,a)) holds
S1[x,h . x]
from FUNCT_2:sch 1(A2);
consider m1, m2 being object such that
A4:
m1 in dom (F_dp1 (t,a))
and
A5:
m2 in dom (F_dp1 (t,a))
and
A6:
m1 <> m2
and
A7:
h . m1 = h . m2
by A1, FINSEQ_4:65;
A9:
S1[m2,h . m2]
by A3, A5;
S1[m1,h . m1]
by A3, A4;
then (F_dp1 (t,a)) . m1 =
h . m2
by A7
.=
(F_dp1 (t,a)) . m2
by A9
;
hence
ex x1, x2 being object st
( x1 in dom (F_dp1 (t,a)) & x2 in dom (F_dp1 (t,a)) & x1 <> x2 & (F_dp1 (t,a)) . x1 = (F_dp1 (t,a)) . x2 )
by A4, A5, A6; verum