for x1, x2, x3, x4, x5, x6, x7 being non pair set holds
( x1 in InputVertices (STC0IStr (x1,x2,x3,x4,x5,x6,x7)) & x2 in InputVertices (STC0IStr (x1,x2,x3,x4,x5,x6,x7)) & x3 in InputVertices (STC0IStr (x1,x2,x3,x4,x5,x6,x7)) & x4 in InputVertices (STC0IStr (x1,x2,x3,x4,x5,x6,x7)) & x5 in InputVertices (STC0IStr (x1,x2,x3,x4,x5,x6,x7)) & x6 in InputVertices (STC0IStr (x1,x2,x3,x4,x5,x6,x7)) & x7 in InputVertices (STC0IStr (x1,x2,x3,x4,x5,x6,x7)) )