let H, v be LTL-formula; :: thesis: for N being strict LTLnode of v st H in the LTLnew of N & ( H is atomic or H is negative ) holds
* N = * (SuccNode1 H,N)

let N be strict LTLnode of v; :: thesis: ( H in the LTLnew of N & ( H is atomic or H is negative ) implies * N = * (SuccNode1 H,N) )
set N1 = SuccNode1 H,N;
assume A1: ( H in the LTLnew of N & ( H is atomic or H is negative ) ) ; :: thesis: * N = * (SuccNode1 H,N)
A3: ( not H is conjunctive & not H is disjunctive & not H is next & not H is Until & not H is Release ) by A1, MODELC_2:78;
then A4: LTLNew1 H = {} by Def203;
A5: LTLNext H = {} by A3, Def205;
set N1O = the LTLold of (SuccNode1 H,N);
set N1N = the LTLnew of (SuccNode1 H,N);
set N1X = the LTLnext of (SuccNode1 H,N);
set NO = the LTLold of N;
set NN = the LTLnew of N;
set NX = the LTLnext of N;
A6: ( the LTLold of (SuccNode1 H,N) = the LTLold of N \/ {H} & the LTLnew of (SuccNode1 H,N) = (the LTLnew of N \ {H}) \/ ((LTLNew1 H) \ the LTLold of N) & the LTLnext of (SuccNode1 H,N) = the LTLnext of N \/ (LTLNext H) ) by A1, Def206;
the LTLold of (SuccNode1 H,N) \/ the LTLnew of (SuccNode1 H,N) = the LTLold of N \/ the LTLnew of N
proof
B1: for a being set st a in the LTLold of (SuccNode1 H,N) \/ the LTLnew of (SuccNode1 H,N) holds
a in the LTLold of N \/ the LTLnew of N
proof
let a be set ; :: thesis: ( a in the LTLold of (SuccNode1 H,N) \/ the LTLnew of (SuccNode1 H,N) implies a in the LTLold of N \/ the LTLnew of N )
assume C1: a in the LTLold of (SuccNode1 H,N) \/ the LTLnew of (SuccNode1 H,N) ; :: thesis: a in the LTLold of N \/ the LTLnew of N
( not a in the LTLold of (SuccNode1 H,N) or a in the LTLold of N or a in {H} ) by A6, XBOOLE_0:def 3;
then C2: ( not a in the LTLold of (SuccNode1 H,N) or a in the LTLold of N or a in the LTLnew of N ) by A1, TARSKI:def 1;
( a in the LTLnew of (SuccNode1 H,N) implies ( a in the LTLnew of N & not a in {H} ) ) by A6, A4, XBOOLE_0:def 5;
hence a in the LTLold of N \/ the LTLnew of N by C1, C2, XBOOLE_0:def 3; :: thesis: verum
end;
for a being set st a in the LTLold of N \/ the LTLnew of N holds
a in the LTLold of (SuccNode1 H,N) \/ the LTLnew of (SuccNode1 H,N)
proof
let a be set ; :: thesis: ( a in the LTLold of N \/ the LTLnew of N implies a in the LTLold of (SuccNode1 H,N) \/ the LTLnew of (SuccNode1 H,N) )
assume C1: a in the LTLold of N \/ the LTLnew of N ; :: thesis: a in the LTLold of (SuccNode1 H,N) \/ the LTLnew of (SuccNode1 H,N)
C2: ( a in the LTLold of N implies a in the LTLold of (SuccNode1 H,N) ) by A6, XBOOLE_0:def 3;
( not a in the LTLnew of N or ( not a in {H} & a in the LTLnew of N ) or ( a in {H} & a in the LTLnew of N ) ) ;
then ( not a in the LTLnew of N or a in the LTLnew of N \ {H} or a in the LTLold of N \/ {H} ) by XBOOLE_0:def 3, XBOOLE_0:def 5;
hence a in the LTLold of (SuccNode1 H,N) \/ the LTLnew of (SuccNode1 H,N) by A6, A4, C1, C2, XBOOLE_0:def 3; :: thesis: verum
end;
hence the LTLold of (SuccNode1 H,N) \/ the LTLnew of (SuccNode1 H,N) = the LTLold of N \/ the LTLnew of N by B1, TARSKI:2; :: thesis: verum
end;
hence * N = * (SuccNode1 H,N) by A6, A5; :: thesis: verum