Hi,

I'm having trouble with constructing proof for the following assertions:

R + S = S + R , commutativity

(R + S) + T = R + (S + T)

R (ST) = (RS) T, associativity

(R+S)T = RT + ST, distributivity

Where R,S,T are regular expressions. + is the union operation and when there is no operator it indicates concatenation.

Can anyone give me some guidance?