reserve i,j for Nat;
reserve i,j for Nat,
  x for variable,
  l for quasi-loci;
reserve C for initialized ConstructorSignature,
  c for constructor OperSymbol of C;
reserve a,a9 for quasi-adjective,
  t,t1,t2 for quasi-term,
  T for quasi-type,

  c for Element of Constructors;

theorem Th37:
  for C being non void Signature for o being OperSymbol of C holds
  (o is nullary implies o is not unary) &
  (o is nullary implies o is not binary) &
  (o is unary implies o is not binary);
