set i = a,k1 <>0_goto ((card I) + 2);
set G = Goto ((card J) + 1);
set IF = if=0 a,k1,I,J;
set IsIF = Initialized (stop (if=0 a,k1,I,J));
reconsider IJ = (I ';' (Goto ((card J) + 1))) ';' J as shiftable Program of SCMPDS ;
if=0 a,k1,I,J = ((a,k1 <>0_goto ((card I) + 2)) ';' (I ';' (Goto ((card J) + 1)))) ';' J by SCMPDS_4:50
.= (a,k1 <>0_goto ((card I) + 2)) ';' IJ by SCMPDS_4:50
.= (Load (a,k1 <>0_goto ((card I) + 2))) ';' IJ by SCMPDS_4:def 4 ;
hence if=0 a,k1,I,J is shiftable ; :: thesis: if=0 a,k1,I,J is parahalting

now

let s be State of SCMPDS ; :: thesis: ( Initialized (stop (if=0 a,k1,I,J)) c= s implies ProgramPart b₁ halts_on b₁ )
assume Initialized (stop (if=0 a,k1,I,J)) c= s ; :: thesis: ProgramPart b₁ halts_on b₁
then A1: s = s +* (Initialized (stop (if=0 a,k1,I,J))) by FUNCT_4:79;
A2: ( J is_closed_on s & J is_halting_on s ) by Th34, Th35;
A3: ( I is_closed_on s & I is_halting_on s ) by Th34, Th35;

per cases ( s . (DataLoc (s . a),k1) = 0 or s . (DataLoc (s . a),k1) <> 0 ) ;

suppose s . (DataLoc (s . a),k1) = 0 ; :: thesis: ProgramPart b₁ halts_on b₁

then if=0 a,k1,I,J is_halting_on s by A3, Th52;
hence ProgramPart s halts_on s by A1, Def3; :: thesis: verum

end;

suppose s . (DataLoc (s . a),k1) <> 0 ; :: thesis: ProgramPart b₁ halts_on b₁

then if=0 a,k1,I,J is_halting_on s by A2, Th53;
hence ProgramPart s halts_on s by A1, Def3; :: thesis: verum

end;

end;

end;

then Initialized (stop (if=0 a,k1,I,J)) is halting by AMI_1:def 26;
hence if=0 a,k1,I,J is parahalting by SCMPDS_4:def 10; :: thesis: verum