fix typo

front/abstract.tex

@@ -2,9 +2,9 @@
 
 Random power-law graphs on $n$ vertices can be defined in different ways.
 One model we study describes graphs where the expected number of vertices
-of degree $x$ is proportional to a power law $x^{-\beta}$, for constant $\beta>0$.
+of degree $x$ is proportional to a power law $1/x^\beta$, for constant $\beta>0$.
 In another model, the exact degree sequence follows the power-law distribution
-and each vertex $i$ has degree $pn/i^{-\beta}$, for $0<p\leq 1$ and $\beta\geq 0$.
+and each vertex $i$ has degree $pn/i^\beta$, for $0<p\leq 1$ and $\beta\geq 0$.
 
 We show that for these models, power-law graphs contain
 ``large'' edge and vertex expanders.