let s be SCM+FSA-State; :: thesis: for s9 being SCM-State holds s +* s9 is SCM+FSA-State
let s9 be SCM-State; :: thesis: s +* s9 is SCM+FSA-State
A1: dom SCM+FSA-OK = SCM+FSA-Memory by FUNCT_2:def 1;
reconsider f = SCM+FSA-OK as non-empty ManySortedSet of SCM+FSA-Memory ;
A2: dom s9 = dom SCM-OK by CARD_3:9
.= SCM-Memory by FUNCT_2:def 1 ;
now end;
then s +* s9 is SCM+FSA-State by A1, A2, PRE_CIRC:6, XBOOLE_1:7;
hence s +* s9 is SCM+FSA-State ; :: thesis: verum