Is there a name for functions with the following property (a la transitive relations)?
If $F(X \cup \{a\}) = y$ and $F(X \cup \{b\}) = y$ then $F(X \cup \{a,b\}) = y$
Is there a name for functions with the following property (a la transitive relations)? If $F(X \cup \{a\}) = y$ and $F(X \cup \{b\}) = y$ then $F(X \cup \{a,b\}) = y$ 

