let ap, bm, cp, dm be non pair set ; :: thesis: for cin being set
for s being State of (BitFTA1Circ (ap,bm,cp,dm,cin))
for a123x, a123y, a123z being Element of BOOLEAN st a123x = s . [<*(GFA1AdderOutput (ap,bm,cp)),cin*>,and2a] & a123y = s . [<*cin,dm*>,and2c] & a123z = s . [<*dm,(GFA1AdderOutput (ap,bm,cp))*>,nor2] holds
(Following s) . (GFA2CarryOutput ((GFA1AdderOutput (ap,bm,cp)),cin,dm)) = 'not' ((a123x 'or' a123y) 'or' a123z)

let cin be set ; :: thesis: for s being State of (BitFTA1Circ (ap,bm,cp,dm,cin))
for a123x, a123y, a123z being Element of BOOLEAN st a123x = s . [<*(GFA1AdderOutput (ap,bm,cp)),cin*>,and2a] & a123y = s . [<*cin,dm*>,and2c] & a123z = s . [<*dm,(GFA1AdderOutput (ap,bm,cp))*>,nor2] holds
(Following s) . (GFA2CarryOutput ((GFA1AdderOutput (ap,bm,cp)),cin,dm)) = 'not' ((a123x 'or' a123y) 'or' a123z)

set S = BitFTA1Str (ap,bm,cp,dm,cin);
set C = BitFTA1Circ (ap,bm,cp,dm,cin);
set A1 = GFA1AdderOutput (ap,bm,cp);
set A2 = GFA2CarryOutput ((GFA1AdderOutput (ap,bm,cp)),cin,dm);
set A1cin = [<*(GFA1AdderOutput (ap,bm,cp)),cin*>,and2a];
set cindm = [<*cin,dm*>,and2c];
set dmA1 = [<*dm,(GFA1AdderOutput (ap,bm,cp))*>,nor2];
let s be State of (BitFTA1Circ (ap,bm,cp,dm,cin)); :: thesis: for a123x, a123y, a123z being Element of BOOLEAN st a123x = s . [<*(GFA1AdderOutput (ap,bm,cp)),cin*>,and2a] & a123y = s . [<*cin,dm*>,and2c] & a123z = s . [<*dm,(GFA1AdderOutput (ap,bm,cp))*>,nor2] holds
(Following s) . (GFA2CarryOutput ((GFA1AdderOutput (ap,bm,cp)),cin,dm)) = 'not' ((a123x 'or' a123y) 'or' a123z)

let a123x, a123y, a123z be Element of BOOLEAN ; :: thesis: ( a123x = s . [<*(GFA1AdderOutput (ap,bm,cp)),cin*>,and2a] & a123y = s . [<*cin,dm*>,and2c] & a123z = s . [<*dm,(GFA1AdderOutput (ap,bm,cp))*>,nor2] implies (Following s) . (GFA2CarryOutput ((GFA1AdderOutput (ap,bm,cp)),cin,dm)) = 'not' ((a123x 'or' a123y) 'or' a123z) )
assume A1: ( a123x = s . [<*(GFA1AdderOutput (ap,bm,cp)),cin*>,and2a] & a123y = s . [<*cin,dm*>,and2c] & a123z = s . [<*dm,(GFA1AdderOutput (ap,bm,cp))*>,nor2] ) ; :: thesis: (Following s) . (GFA2CarryOutput ((GFA1AdderOutput (ap,bm,cp)),cin,dm)) = 'not' ((a123x 'or' a123y) 'or' a123z)
A2: ( [<*(GFA1AdderOutput (ap,bm,cp)),cin*>,and2a] in the carrier of (BitFTA1Str (ap,bm,cp,dm,cin)) & [<*cin,dm*>,and2c] in the carrier of (BitFTA1Str (ap,bm,cp,dm,cin)) ) by Th14;
A3: ( [<*dm,(GFA1AdderOutput (ap,bm,cp))*>,nor2] in the carrier of (BitFTA1Str (ap,bm,cp,dm,cin)) & dom s = the carrier of (BitFTA1Str (ap,bm,cp,dm,cin)) ) by Th14, CIRCUIT1:3;
InnerVertices (BitFTA1Str (ap,bm,cp,dm,cin)) = the carrier' of (BitFTA1Str (ap,bm,cp,dm,cin)) by FACIRC_1:37;
then GFA2CarryOutput ((GFA1AdderOutput (ap,bm,cp)),cin,dm) in the carrier' of (BitFTA1Str (ap,bm,cp,dm,cin)) by Th15;
hence (Following s) . (GFA2CarryOutput ((GFA1AdderOutput (ap,bm,cp)),cin,dm)) = nor3 . (s * <*[<*(GFA1AdderOutput (ap,bm,cp)),cin*>,and2a],[<*cin,dm*>,and2c],[<*dm,(GFA1AdderOutput (ap,bm,cp))*>,nor2]*>) by FACIRC_1:35
.= nor3 . <*a123x,a123y,a123z*> by A1, A2, A3, FINSEQ_2:126
.= 'not' ((a123x 'or' a123y) 'or' a123z) by TWOSCOMP:def 28 ;
:: thesis: verum