Question: Can I set variable properties

Is it possible to assign certain properties to certain variables in Maple, and have them obey those properties?

In other words, I want to work in complex numbers. I want z to be complex and to obey the rules of complex numbers. How can I declare z element of Complex and then Maple won't do complex illegal operations (or it will do them correctly). Sort of like "I" works according to the rules of sqrt(-1). Except that I is built in.

Another example would be to declare a variable as not allowed to equal 0. Then, if it gets set to zero, Maple raises an error, or prohibits it, or something. Get it?

If yes, how do I do it? Can you tell me what to read about to learn it (and a good starter example would be nice, too :D ).

I am using a student version of Maple 14 on Win7 x64. I have some programming background, but am baffled by most of Maple.

Thanks for your help.

-J