A2: rng ((SCM+FSA-Memory --> (INT *)) +* SCM-OK) c= {INT,(INT *)} \/ {NAT}
proof
let y be set ; :: according to TARSKI:def 3 :: thesis: ( not y in rng ((SCM+FSA-Memory --> (INT *)) +* SCM-OK) or y in {INT,(INT *)} \/ {NAT} )
assume y in rng ((SCM+FSA-Memory --> (INT *)) +* SCM-OK) ; :: thesis: y in {INT,(INT *)} \/ {NAT}
then consider z being set such that
A4: z in dom ((SCM+FSA-Memory --> (INT *)) +* SCM-OK) and
A5: ((SCM+FSA-Memory --> (INT *)) +* SCM-OK) . z = y by FUNCT_1:def 3;
dom ((SCM+FSA-Memory --> (INT *)) +* SCM-OK) = (dom (SCM+FSA-Memory --> (INT *))) \/ (dom SCM-OK) by FUNCT_4:def 1
.= ((dom (SCM+FSA-Memory --> (INT *))) \ (dom SCM-OK)) \/ (dom SCM-OK) by XBOOLE_1:39 ;
then A6: ( z in (dom (SCM+FSA-Memory --> (INT *))) \ (dom SCM-OK) or z in dom SCM-OK ) by A4, XBOOLE_0:def 3;
per cases ( z in (dom (SCM+FSA-Memory --> (INT *))) \ (dom SCM-OK) or z in dom SCM-OK ) by A6;
end;
end;
dom ((SCM+FSA-Memory --> (INT *)) +* SCM-OK) = (dom (SCM+FSA-Memory --> (INT *))) \/ (dom SCM-OK) by FUNCT_4:def 1
.= SCM+FSA-Memory \/ (dom SCM-OK) by FUNCOP_1:13
.= SCM+FSA-Memory \/ SCM-Memory by FUNCT_2:def 1
.= SCM+FSA-Memory by XBOOLE_1:7, XBOOLE_1:12 ;
then dom ((SCM+FSA-Memory --> (INT *)) +* SCM-OK) = SCM+FSA-Memory
.= SCM+FSA-Memory ;
hence (SCM+FSA-Memory --> (INT *)) +* SCM-OK is Function of SCM+FSA-Memory,({INT,(INT *)} \/ {NAT}) by A2, FUNCT_2:def 1, RELSET_1:4; :: thesis: verum