Math Help - Prove the following

1. Prove the following

Prove:

(1) R isTotalOnA ⇔ (∀x : A • ∃ y : Y • (x , y) ϵ R)

(2) R ; (S ∩ T) ⊆ (R ; S) ∩ (R ; T)

2. Originally Posted by rnuravvk
Prove:
(1) R isTotalOnA ⇔ (∀x : A • ∃ y : Y • (x , y) ϵ R)
WHAT?
What does #1 & #2 say? I have no idea what those symbols mean.

3. The symbol " ; " is the symbol for composition

4. Originally Posted by rnuravvk
The symbol " ; " is the symbol for composition
Not good enough.
Define all the terms.
What is "TotalonA"?
What does $\bullet$ mean?
These happen to be nonstandard symbols.

EDIT:
Why not learn to post in symbols? You can use LaTeX tags
$$\left( {\exists x} \right)$$ gives $\left( {\exists x} \right)$ is exists
$$\left( {\forall x} \right)$$ gives $\left( {\forall x} \right)$ is for all
$$\cup$$ gives $\cup$ is union
$$\cap$$ gives $\cap$ is intersection
$$\subseteq$$ gives $\subseteq$ is subset
$$\cup$$ gives $\cup$ is union
$$\in$$ gives $\in$ is element
$$\emptyset$$ gives $\emptyset$ is emptyset
$$\wedge$$ gives $\wedge$ is or
$$\vee$$ gives $\vee$ is and
$$\sqrt{x+1}$$ gives $\sqrt{x+1}$