let x, y, c be non pair set ; :: thesis: for s being State of (BorrowCirc (x,y,c))
for a1, a3 being Element of BOOLEAN st a1 = s . x & a3 = s . c holds
(Following s) . [<*x,c*>,and2a] = ('not' a1) '&' a3
reconsider a = y as Vertex of (BorrowStr (x,y,c)) by Th6;
let s be State of (BorrowCirc (x,y,c)); :: thesis: for a1, a3 being Element of BOOLEAN st a1 = s . x & a3 = s . c holds
(Following s) . [<*x,c*>,and2a] = ('not' a1) '&' a3
s . a is Element of BOOLEAN ;
hence for a1, a3 being Element of BOOLEAN st a1 = s . x & a3 = s . c holds
(Following s) . [<*x,c*>,and2a] = ('not' a1) '&' a3 by Lm1; :: thesis: verum