defpred S1[ set , set , set ] means verum;
set S0 = 1GateCircStr <*> ,((0 -tuples_on BOOLEAN ) --> TRUE );
set Sn = n -BitGFA1Str x,y;
set o0 = [<*> ,((0 -tuples_on BOOLEAN ) --> TRUE )];
deffunc H1( non empty ManySortedSign , set , Nat) -> ManySortedSign = $1 +* (BitGFA1Str (x . ($3 + 1)),(y . ($3 + 1)),$2);
deffunc H2( set , Nat) -> Element of InnerVertices (GFA1CarryStr (x . ($2 + 1)),(y . ($2 + 1)),$1) = GFA1CarryOutput (x . ($2 + 1)),(y . ($2 + 1)),$1;
consider f, g being ManySortedSet of NAT such that
A13: n -BitGFA1Str x,y = f . n and
A14: f . 0 = 1GateCircStr <*> ,((0 -tuples_on BOOLEAN ) --> TRUE ) and
A15: g . 0 = [<*> ,((0 -tuples_on BOOLEAN ) --> TRUE )] and
A16: for n being Nat
for S being non empty ManySortedSign
for z being set st S = f . n & z = g . n holds
( f . (n + 1) = H1(S,z,n) & g . (n + 1) = H2(z,n) ) by Def5;
defpred S2[ Nat] means ex S being non empty ManySortedSign st
( S = f . $1 & g . $1 in InnerVertices S );
InnerVertices (1GateCircStr <*> ,((0 -tuples_on BOOLEAN ) --> TRUE )) = {[<*> ,((0 -tuples_on BOOLEAN ) --> TRUE )]} by CIRCCOMB:49;
then [<*> ,((0 -tuples_on BOOLEAN ) --> TRUE )] in InnerVertices (1GateCircStr <*> ,((0 -tuples_on BOOLEAN ) --> TRUE )) by TARSKI:def 1;
then A17: S2[ 0 ] by A14, A15;
A18: for i being Nat st S2[i] holds
S2[i + 1]
proof
let i be Nat; :: thesis: ( S2[i] implies S2[i + 1] )
assume that
A19: ex S being non empty ManySortedSign st
( S = f . i & g . i in InnerVertices S ) and
A20: for S being non empty ManySortedSign st S = f . (i + 1) holds
not g . (i + 1) in InnerVertices S ; :: thesis: contradiction
consider S being non empty ManySortedSign such that
A21: S = f . i and
g . i in InnerVertices S by A19;
GFA1CarryOutput (x . (i + 1)),(y . (i + 1)),(g . i) in InnerVertices (BitGFA1Str (x . (i + 1)),(y . (i + 1)),(g . i)) by GFACIRC1:82;
then A22: GFA1CarryOutput (x . (i + 1)),(y . (i + 1)),(g . i) in InnerVertices (S +* (BitGFA1Str (x . (i + 1)),(y . (i + 1)),(g . i))) by FACIRC_1:22;
A23: f . (i + 1) = S +* (BitGFA1Str (x . (i + 1)),(y . (i + 1)),(g . i)) by A16, A21;
g . (i + 1) = GFA1CarryOutput (x . (i + 1)),(y . (i + 1)),(g . i) by A16, A21;
hence contradiction by A20, A22, A23; :: thesis: verum
end;
for i being Nat holds S2[i] from NAT_1:sch 2(A17, A18);
 then ex S being non empty ManySortedSign st
( S = f . n & g . n in InnerVertices S ) ;
then reconsider o = g . n as Element of InnerVertices (n -BitGFA1Str x,y) by A13;
take o ; :: thesis: ex h being ManySortedSet of NAT st
( o = h . n & h . 0 = [<*> ,((0 -tuples_on BOOLEAN ) --> TRUE )] & ( for n being Nat holds h . (n + 1) = GFA1CarryOutput (x . (n + 1)),(y . (n + 1)),(h . n) ) )
take g ; :: thesis: ( o = g . n & g . 0 = [<*> ,((0 -tuples_on BOOLEAN ) --> TRUE )] & ( for n being Nat holds g . (n + 1) = GFA1CarryOutput (x . (n + 1)),(y . (n + 1)),(g . n) ) )
thus ( o = g . n & g . 0 = [<*> ,((0 -tuples_on BOOLEAN ) --> TRUE )] ) by A15; :: thesis: for n being Nat holds g . (n + 1) = GFA1CarryOutput (x . (n + 1)),(y . (n + 1)),(g . n)
let i be Nat; :: thesis: g . (i + 1) = GFA1CarryOutput (x . (i + 1)),(y . (i + 1)),(g . i)
A24: ex S being non empty ManySortedSign ex x being set st
( S = f . 0 & x = g . 0 & S1[S,x, 0 ] ) by A14;
A25: for n being Nat
for S being non empty ManySortedSign
for x being set st S = f . n & x = g . n & S1[S,x,n] holds
S1[H1(S,x,n),H2(x,n),n + 1] ;
for n being Nat ex S being non empty ManySortedSign st
( S = f . n & S1[S,g . n,n] ) from CIRCCMB2:sch 2(A24, A16, A25);
 then ex S being non empty ManySortedSign st S = f . i ;
hence g . (i + 1) = GFA1CarryOutput (x . (i + 1)),(y . (i + 1)),(g . i) by A16; :: thesis: verum