let x, y, c be non pair set ; :: thesis: for s being State of (MajorityCirc x,y,c)
for a1, a2, a3 being Element of BOOLEAN st a1 = s . [<*x,y*>,'&' ] & a2 = s . [<*y,c*>,'&' ] & a3 = s . [<*c,x*>,'&' ] holds
(Following s) . (MajorityOutput x,y,c) = (a1 'or' a2) 'or' a3
let s be State of (MajorityCirc x,y,c); :: thesis: for a1, a2, a3 being Element of BOOLEAN st a1 = s . [<*x,y*>,'&' ] & a2 = s . [<*y,c*>,'&' ] & a3 = s . [<*c,x*>,'&' ] holds
(Following s) . (MajorityOutput x,y,c) = (a1 'or' a2) 'or' a3
let a1, a2, a3 be Element of BOOLEAN ; :: thesis: ( a1 = s . [<*x,y*>,'&' ] & a2 = s . [<*y,c*>,'&' ] & a3 = s . [<*c,x*>,'&' ] implies (Following s) . (MajorityOutput x,y,c) = (a1 'or' a2) 'or' a3 )
assume A1:
( a1 = s . [<*x,y*>,'&' ] & a2 = s . [<*y,c*>,'&' ] & a3 = s . [<*c,x*>,'&' ] )
; :: thesis: (Following s) . (MajorityOutput x,y,c) = (a1 'or' a2) 'or' a3
set xy = [<*x,y*>,'&' ];
set yc = [<*y,c*>,'&' ];
set cx = [<*c,x*>,'&' ];
set S = MajorityStr x,y,c;
A2:
InnerVertices (MajorityStr x,y,c) = the carrier' of (MajorityStr x,y,c)
by Th37;
A3:
dom s = the carrier of (MajorityStr x,y,c)
by CIRCUIT1:4;
reconsider xy = [<*x,y*>,'&' ], yc = [<*y,c*>,'&' ], cx = [<*c,x*>,'&' ] as Element of InnerVertices (MajorityStr x,y,c) by Th73;
thus (Following s) . (MajorityOutput x,y,c) =
or3 . (s * <*xy,yc,cx*>)
by A2, Th35
.=
or3 . <*a1,a2,a3*>
by A1, A3, FINSEQ_2:146
.=
(a1 'or' a2) 'or' a3
by Def7
; :: thesis: verum