String Theory: Multiverse w/ Same Constants?

[tribdog]

whenever I read an article about string theory stating that our Universe may be one of many making up a Multiverse, they always add, "each having different physical constants"
Do they have to have different constants? Does the math require it? or could the constants be constant?

 

[meteor]

Glad to see you here
this multiverse that you are speaking about inhabits in something called the moduli space, and each of the universes is called a vacuum. The set of all the vacua is often referred as The Landscape
The fact that there are so many vacua is imposed by the maths. You have M-theory that is 11-dimensional, and you need to compactify it to the 3+1 dimensional world that we live in, but there are millions of different ways to compactify M-theory, that's why there are so many vacua. So yes, the fact that they have different constants is imposed by the math

 

[jujio77]

The math doesn't tell you how the to compactify the spaces though...does it? If so, each space compactify in the same way, yet it seems unlikely? It would be nice if someone found a mechansim which describes compactification process.