let MS be non empty trivial non void segmental ManySortedSign ; for A being non-empty MSAlgebra of MS st the carrier of MS = {0 } holds
MSAlg (1-Alg A) = MSAlgebra(# the Sorts of A,the Charact of A #)
let A be non-empty MSAlgebra of MS; ( the carrier of MS = {0 } implies MSAlg (1-Alg A) = MSAlgebra(# the Sorts of A,the Charact of A #) )
reconsider c = the_sort_of (MSAlg (1-Alg A)) as Component of the Sorts of (MSAlg (1-Alg A)) by MSUALG_1:def 17;
assume
the carrier of MS = {0 }
; MSAlg (1-Alg A) = MSAlgebra(# the Sorts of A,the Charact of A #)
then
MSSign (1-Alg A) = ManySortedSign(# the carrier of MS,the carrier' of MS,the Arity of MS,the ResultSort of MS #)
by Th23;
then reconsider M1A = MSAlg (1-Alg A) as strict MSAlgebra of MS ;
reconsider M1A = M1A as strict non-empty MSAlgebra of MS by MSUALG_1:def 8;
A1:
1-Alg M1A = UAStr(# (the_sort_of M1A),(the_charact_of M1A) #)
by MSUALG_1:def 19;
reconsider c = c as Component of the Sorts of M1A ;
A2:
1-Alg (MSAlg (1-Alg A)) = UAStr(# (the_sort_of (MSAlg (1-Alg A))),(the_charact_of (MSAlg (1-Alg A))) #)
by MSUALG_1:def 19;
then A3: the charact of (1-Alg A) =
the_charact_of (MSAlg (1-Alg A))
by MSUALG_1:15
.=
the Charact of M1A
by MSUALG_1:def 18
.=
the charact of (1-Alg M1A)
by A1, MSUALG_1:def 18
;
c = the_sort_of M1A
by MSUALG_1:def 17;
then
the carrier of (1-Alg A) = the carrier of (1-Alg M1A)
by A2, A1, MSUALG_1:15;
hence
MSAlg (1-Alg A) = MSAlgebra(# the Sorts of A,the Charact of A #)
by A3, Th24; verum