let MS be non void 1 -element segmental ManySortedSign ; for A being non-empty MSAlgebra of MS
for B being non-empty MSSubAlgebra of A holds the carrier of (1-Alg B) is Subset of (1-Alg A)
let A be non-empty MSAlgebra of MS; for B being non-empty MSSubAlgebra of A holds the carrier of (1-Alg B) is Subset of (1-Alg A)
let B be non-empty MSSubAlgebra of A; the carrier of (1-Alg B) is Subset of (1-Alg A)
the Sorts of B is MSSubset of A
by MSUALG_2:def 9;
then A1:
the Sorts of B c= the Sorts of A
by PBOOLE:def 18;
1-Alg B = UAStr(# (the_sort_of B),(the_charact_of B) #)
by MSUALG_1:def 14;
then reconsider c = the carrier of (1-Alg B) as Component of the Sorts of B by MSUALG_1:def 12;
1-Alg A = UAStr(# (the_sort_of A),(the_charact_of A) #)
by MSUALG_1:def 14;
then reconsider d = the carrier of (1-Alg A) as Component of the Sorts of A by MSUALG_1:def 12;
A2:
dom the Sorts of A = the carrier of MS
by PARTFUN1:def 2;
then consider dr being set such that
A3:
dr in the carrier of MS
and
A4:
d = the Sorts of A . dr
by FUNCT_1:def 3;
dom the Sorts of A = dom the Sorts of B
by A2, PARTFUN1:def 2;
then consider cr being set such that
A5:
cr in the carrier of MS
and
A6:
c = the Sorts of B . cr
by A2, FUNCT_1:def 3;
cr = dr
by A5, A3, STRUCT_0:def 10;
hence
the carrier of (1-Alg B) is Subset of (1-Alg A)
by A1, A5, A6, A4, PBOOLE:def 2; verum