Definition:Combinable

Definition
Let:


 * $$\mathcal R_1 \subseteq S_1 \times T_1$$ be a relation on $$S_1 \times T_1$$;


 * $$\mathcal R_2 \subseteq S_2 \times T_2$$ be a relation on $$S_2 \times T_2$$;


 * $$X = S_1 \cap S_2$$.

If $$\mathcal R_1$$ and $$\mathcal R_2$$ agree on $$X$$, they are said to be combinable.

Note
The concept is usually seen in the context of mappings.