let H, v be LTL-formula; for s0, s1 being strict elementary LTLnode over v st s1 is_next_of s0 & H in the LTLold of s1 holds
( ( H is conjunctive implies ( the_left_argument_of H in the LTLold of s1 & the_right_argument_of H in the LTLold of s1 ) ) & ( ( not H is disjunctive & not H is Until ) or the_left_argument_of H in the LTLold of s1 or the_right_argument_of H in the LTLold of s1 ) & ( H is next implies the_argument_of H in the LTLnext of s1 ) & ( H is Release implies the_right_argument_of H in the LTLold of s1 ) )
let s0, s1 be strict elementary LTLnode over v; ( s1 is_next_of s0 & H in the LTLold of s1 implies ( ( H is conjunctive implies ( the_left_argument_of H in the LTLold of s1 & the_right_argument_of H in the LTLold of s1 ) ) & ( ( not H is disjunctive & not H is Until ) or the_left_argument_of H in the LTLold of s1 or the_right_argument_of H in the LTLold of s1 ) & ( H is next implies the_argument_of H in the LTLnext of s1 ) & ( H is Release implies the_right_argument_of H in the LTLold of s1 ) ) )
assume that
A1:
s1 is_next_of s0
and
A2:
H in the LTLold of s1
; ( ( H is conjunctive implies ( the_left_argument_of H in the LTLold of s1 & the_right_argument_of H in the LTLold of s1 ) ) & ( ( not H is disjunctive & not H is Until ) or the_left_argument_of H in the LTLold of s1 or the_right_argument_of H in the LTLold of s1 ) & ( H is next implies the_argument_of H in the LTLnext of s1 ) & ( H is Release implies the_right_argument_of H in the LTLold of s1 ) )
consider L being FinSequence such that
A3:
1 <= len L
and
A4:
L is_Finseq_for v
and
A5:
L . 1 = 'X' s0
and
A6:
L . (len L) = s1
by A1;
A7:
CastNode ((L . 1),v) = 'X' s0
by A5, Def16;
set n = len L;
A8:
CastNode ((L . (len L)),v) = s1
by A6, Def16;
1 < len L
by A2, A3, A5, A6, XXREAL_0:1;
then consider m being Nat such that
A9:
( 1 <= m & m < len L )
and
A10:
( not H in the LTLold of (CastNode ((L . m),v)) & H in the LTLold of (CastNode ((L . (m + 1)),v)) )
by A2, A4, A8, A7, Th27;
consider N1, N2 being strict LTLnode over v such that
A11:
N1 = L . m
and
A12:
N2 = L . (m + 1)
and
A13:
N2 is_succ_of N1
by A4, A9;
A14:
CastNode ((L . m),v) = N1
by A11, Def16;
then A15:
the LTLold of N1 c= the LTLold of s1
by A4, A8, A9, Th31;
set m1 = m + 1;
A16:
( m + 1 <= len L & 1 <= m + 1 )
by A9, NAT_1:13;
A17:
CastNode ((L . (m + 1)),v) = N2
by A12, Def16;
then A18:
N2 is_succ_of N1,H
by A10, A13, A14, Th28;
the LTLnew of (CastNode ((L . (len L)),v)) = {} v
by A8, Def11;
then A19:
the LTLnew of N2 c= the LTLold of s1
by A4, A8, A17, A16, Th34;
A20:
( H is conjunctive implies ( the_left_argument_of H in the LTLold of s1 & the_right_argument_of H in the LTLold of s1 ) )
A27:
( H is Release implies the_right_argument_of H in the LTLold of s1 )
A35:
( ( not H is disjunctive & not H is Until ) or the_left_argument_of H in the LTLold of s1 or the_right_argument_of H in the LTLold of s1 )
A43:
the LTLnext of N2 c= the LTLnext of s1
by A4, A8, A17, A16, Th31;
( H is next implies the_argument_of H in the LTLnext of s1 )
hence
( ( H is conjunctive implies ( the_left_argument_of H in the LTLold of s1 & the_right_argument_of H in the LTLold of s1 ) ) & ( ( not H is disjunctive & not H is Until ) or the_left_argument_of H in the LTLold of s1 or the_right_argument_of H in the LTLold of s1 ) & ( H is next implies the_argument_of H in the LTLnext of s1 ) & ( H is Release implies the_right_argument_of H in the LTLold of s1 ) )
by A20, A35, A27; verum