A1: dom F = [:J,K:] by FUNCT_2:def 1;
reconsider F' = F as ManySortedSet of ;
for j being set st j in J holds
(curry F') . j is Function of ((J --> K) . j),((J --> D) . j)
proof
let j be set ; :: thesis: ( j in J implies (curry F') . j is Function of ((J --> K) . j),((J --> D) . j) )
assume A2: j in J ; :: thesis: (curry F') . j is Function of ((J --> K) . j),((J --> D) . j)
then A3: ( (J --> K) . j = K & (J --> D) . j = D ) by FUNCOP_1:13;
J = dom (curry F) by A1, FUNCT_5:31;
then reconsider G = (curry F') . j as Function by A2, FUNCT_5:37;
consider g being Function such that
A4: (curry F') . j = g and
A5: dom g = K and
A6: rng g c= rng F' and
for k being set st k in K holds
g . k = F' . j,k by A1, A2, FUNCT_5:36;
rng F c= D ;
then rng g c= D by A6, XBOOLE_1:1;
then reconsider g = g as Function of K,D by A5, FUNCT_2:def 1, RELSET_1:11;
G = g by A4;
hence (curry F') . j is Function of ((J --> K) . j),((J --> D) . j) by A3; :: thesis: verum
end;
hence curry F is DoubleIndexedSet of J --> K,D by PBOOLE:def 18; :: thesis: verum