reserve S for non empty non void ManySortedSign,
  V for non-empty ManySortedSet of the carrier of S,
  A for non-empty MSAlgebra over S,
  X for non empty Subset of S-Terms V,
  t for Element of X;

theorem
  for v being Vertex of X-CircuitStr
  holds (the Sorts of X-Circuit A).v = the_sort_of (v, A) by Def4;
