(*****  StrictSUB *****)


Record StrictSUB (A B : Ens) : Prop := 
  {StrictSUB_sub : SUB A B; StrictSUB_neq : ~ EQ A B}.(*****  StrictSUB *****)


Record StrictSUB (A B : Ens) : Prop := 
  {StrictSUB_sub : SUB A B; StrictSUB_neq : ~ EQ A B}.(*****  StrictSUB *****)


Record StrictSUB (A B : Ens) : Prop := 
  {StrictSUB_sub : SUB A B; StrictSUB_neq : ~ EQ A B}.

Theorem StrictSUB_trans1 : forall (A B C : Ens) (h : StrictSUB A B) (k : SUB B C), StrictSUB A C.