theorem Th80: :: GFACIRC1:80

for x, y, z being set holds
( [<*x,y*>,and2a] in InnerVertices (GFA2CarryStr (x,y,z)) & [<*y,z*>,and2c] in InnerVertices (GFA2CarryStr (x,y,z)) & [<*z,x*>,nor2] in InnerVertices (GFA2CarryStr (x,y,z)) & GFA2CarryOutput (x,y,z) in InnerVertices (GFA2CarryStr (x,y,z)) )