Suppose we have a tree $T = (V,E)$, in which each nodes $v_i \in V$ has a probability $p_i$ to vanish. Let $v_0\in V$, we define random variable $\boldsymbol{X} = \boldsymbol{X}(T, v_0)$ stands for the size (number of nodes) of connected component which includes $v_0$. To illustrate the problem more precisely, note that we could write a formula about MGF of $\boldsymbol{X}$ like (regarding $v_0$ as the root of $T$) $$ E[\exp(t \cdot \boldsymbol{X}(T,v_0))] = p_0 + (1-p_0)\exp(t)\prod_{\text{subtree}\ T_i \ \text{for} \ v_0 \text{'s child}\ v_i} E[\exp(t \cdot \boldsymbol{X}(T_i,v_i))].$$ Since this problem looks very natural, I tend to believe that some works have be done for this. However it is hard for me to search them out (I have used Google Scholar to try it but failed). Could you give me some references on this problem?
PS: feel free to edit this post if you want, it would help ^_^