Are the following statements true or false?

 1. The set of all 's that are in the domain of and where is in the domain of correctly describes the domain of .

 2. If is an element of the domain of , then is an element of the domain of .

 3. For any relation , it must be that as long as is a constant.

 4. If is in the domain of , then is in the domain of .

 5. If , then .

 6. as long as is in both the domain of and in the domain of .