let am, bm, cm, dm be non pair set ; :: thesis: for cin being set
for s being State of (BitFTA3Circ (am,bm,cm,dm,cin))
for a123x, a123y, a123z being Element of BOOLEAN st a123x = s . [<*(GFA3AdderOutput (am,bm,cm)),cin*>,nor2] & a123y = s . [<*cin,dm*>,nor2] & a123z = s . [<*dm,(GFA3AdderOutput (am,bm,cm))*>,nor2] holds
(Following s) . (GFA3CarryOutput ((GFA3AdderOutput (am,bm,cm)),cin,dm)) = 'not' ((a123x 'or' a123y) 'or' a123z)

let cin be set ; :: thesis: for s being State of (BitFTA3Circ (am,bm,cm,dm,cin))
for a123x, a123y, a123z being Element of BOOLEAN st a123x = s . [<*(GFA3AdderOutput (am,bm,cm)),cin*>,nor2] & a123y = s . [<*cin,dm*>,nor2] & a123z = s . [<*dm,(GFA3AdderOutput (am,bm,cm))*>,nor2] holds
(Following s) . (GFA3CarryOutput ((GFA3AdderOutput (am,bm,cm)),cin,dm)) = 'not' ((a123x 'or' a123y) 'or' a123z)

set S = BitFTA3Str (am,bm,cm,dm,cin);
set C = BitFTA3Circ (am,bm,cm,dm,cin);
set A1 = GFA3AdderOutput (am,bm,cm);
set A2 = GFA3CarryOutput ((GFA3AdderOutput (am,bm,cm)),cin,dm);
set A1cin = [<*(GFA3AdderOutput (am,bm,cm)),cin*>,nor2];
set cindm = [<*cin,dm*>,nor2];
set dmA1 = [<*dm,(GFA3AdderOutput (am,bm,cm))*>,nor2];
let s be State of (BitFTA3Circ (am,bm,cm,dm,cin)); :: thesis: for a123x, a123y, a123z being Element of BOOLEAN st a123x = s . [<*(GFA3AdderOutput (am,bm,cm)),cin*>,nor2] & a123y = s . [<*cin,dm*>,nor2] & a123z = s . [<*dm,(GFA3AdderOutput (am,bm,cm))*>,nor2] holds
(Following s) . (GFA3CarryOutput ((GFA3AdderOutput (am,bm,cm)),cin,dm)) = 'not' ((a123x 'or' a123y) 'or' a123z)

let a123x, a123y, a123z be Element of BOOLEAN ; :: thesis: ( a123x = s . [<*(GFA3AdderOutput (am,bm,cm)),cin*>,nor2] & a123y = s . [<*cin,dm*>,nor2] & a123z = s . [<*dm,(GFA3AdderOutput (am,bm,cm))*>,nor2] implies (Following s) . (GFA3CarryOutput ((GFA3AdderOutput (am,bm,cm)),cin,dm)) = 'not' ((a123x 'or' a123y) 'or' a123z) )
assume A1: ( a123x = s . [<*(GFA3AdderOutput (am,bm,cm)),cin*>,nor2] & a123y = s . [<*cin,dm*>,nor2] & a123z = s . [<*dm,(GFA3AdderOutput (am,bm,cm))*>,nor2] ) ; :: thesis: (Following s) . (GFA3CarryOutput ((GFA3AdderOutput (am,bm,cm)),cin,dm)) = 'not' ((a123x 'or' a123y) 'or' a123z)
A2: ( [<*(GFA3AdderOutput (am,bm,cm)),cin*>,nor2] in the carrier of (BitFTA3Str (am,bm,cm,dm,cin)) & [<*cin,dm*>,nor2] in the carrier of (BitFTA3Str (am,bm,cm,dm,cin)) ) by Th34;
A3: ( [<*dm,(GFA3AdderOutput (am,bm,cm))*>,nor2] in the carrier of (BitFTA3Str (am,bm,cm,dm,cin)) & dom s = the carrier of (BitFTA3Str (am,bm,cm,dm,cin)) ) by Th34, CIRCUIT1:3;
InnerVertices (BitFTA3Str (am,bm,cm,dm,cin)) = the carrier' of (BitFTA3Str (am,bm,cm,dm,cin)) by FACIRC_1:37;
then GFA3CarryOutput ((GFA3AdderOutput (am,bm,cm)),cin,dm) in the carrier' of (BitFTA3Str (am,bm,cm,dm,cin)) by Th35;
hence (Following s) . (GFA3CarryOutput ((GFA3AdderOutput (am,bm,cm)),cin,dm)) = nor3 . (s * <*[<*(GFA3AdderOutput (am,bm,cm)),cin*>,nor2],[<*cin,dm*>,nor2],[<*dm,(GFA3AdderOutput (am,bm,cm))*>,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