Is it wise to use system methods when it comes to using static variables for recursive?

http://www.salesforce.com/us/developer/docs/apexcode/Content/apex_methods_system_system.htm

Using IsBatch() and ISfuture() context I feel the static variables need to be used to can be minimized

Instead of doing 

public class abc{
if(static_variable == false){
// do something
static_variable = true;
}
}


try: 

public class abc{
if(isBatch() || Isfuture()){

}
}


Just in case there are multiple batch jobs that are being executed Instead of setting multiple static variable references, this way one check on the class to find if there are batch/future process.

Control Fields vs Heap "Mock" Fields for Branching Trigger Behavior
I want to get this M in LaTeX:



I don't get this style using \mathcal{M}, \mathbb{M} nor \mathfrak{M}.

How can I get it?
I don't want to change the font of the whole document, I just want to insert that M with that style.
