Hashing: Fix a typo

06-hash/hash.tex

@@ -128,7 +128,7 @@ $h_{a,b}(x) = ((ax+b) \bmod p) \bmod m$.
 Let $x,y$ be two distinct numbers in $[p]$.
 First, we will examine the behavior of linear functions taken modulo~$p$
 without the final modulo~$m$ and without the restriction $a\ne 0$.
-For an arbitrary pair $(a,b)=[p]^2$ of parameters, we define
+For an arbitrary pair $(a,b)\in [p]^2$ of parameters, we define
 $$\eqalign{
 	r & = (ax+b) \bmod p, \cr
 	s & = (ay+b) \bmod p. \cr