is mentioned by

Thm* c1:Collection(T). c1 c1	[col_le_reflexive]
Thm* a,b,c:Collection(T). a b b c a c	[col_le_transitivity]
Thm* c1,c2:Collection(T). c1 = c2 c1 c2	[col_le_weakening]
Thm* c:Collection(T). < > c	[col_none_le]

Try larger context: GenAutomata