let s1, s2 be State of SCMPDS ; for I, J being Program of SCMPDS st DataPart s1 = DataPart s2 holds
s1 +* (Initialized I),s2 +* (Initialized J) equal_outside NAT
let I, J be Program of SCMPDS ; ( DataPart s1 = DataPart s2 implies s1 +* (Initialized I),s2 +* (Initialized J) equal_outside NAT )
assume A1:
DataPart s1 = DataPart s2
; s1 +* (Initialized I),s2 +* (Initialized J) equal_outside NAT
set II = Initialized I;
set S1 = s1 +* (Initialized I);
set IJ = Initialized J;
set S2 = s2 +* (Initialized J);
A2:
( IC (s1 +* (Initialized I)) = 0 & IC (s2 +* (Initialized J)) = 0 )
by FUNCT_4:26, SCMPDS_5:18;
DataPart (s1 +* (Initialized I)) =
DataPart s1
by Th9
.=
DataPart (s2 +* (Initialized J))
by A1, Th9
;
hence
s1 +* (Initialized I),s2 +* (Initialized J) equal_outside NAT
by A2, Th4; verum