File &rarr; Import will load other scenes into current scene. File &rarr; Export allows you to conditionally export things from scenes. 

PS: Yes its as obvious as that. But depends on your rig whether it will work (it usually does that's what the namespace is for). Maya does not enforce sanity.

Importing models from another maya project
I have attempted to calculate the number of unlabelled bipartite graphs as follows:


  Let $G = (V_1, V_2, E)$ be a bipartite graph on $n$ vertices with $|V_1| = m$ and $|V_2| = n-m$. Assume without loss of generality that $|V_1| \leq |V_2|$ so $m \leq \left\lfloor \frac{n}{2} \right\rfloor$. If $G$ is complete bipartite then it has $m(n-m)$ edges since each of the vertices in $V_1$ is connected to each in $V_2$. Thus, the total number of bipartite graphs with parts of size $m$ and $n-m$ is $2^{m(n-m)}$. In order to find the total number of possible bipartite graphs on $n$ vertices we sum over all possible $m$:
  \begin{align}
\sum^{\left\lfloor \frac{n}{2} \right\rfloor}_{m=1} 2^{m(n-m)}
\end{align}


However, I notice that I have counted labelled bipartite graphs where I need the number of unlabelled graphs. I'm struggling to see how to account for this.
