diff --git a/06-hash/hash.tex b/06-hash/hash.tex
index 7e12db329ecee5b6ebeec0a2313b516f22d449e6..54efa1185be6c8a6dc46e4c690f59da58e691e8c 100644
--- a/06-hash/hash.tex
+++ b/06-hash/hash.tex
@@ -134,7 +134,7 @@ ${\cal L} = \{ h_{a,b} \mid a,b\in [p] \}$ from $[p]$ to $[m]$, where
 $h_{a,b}(x) = ((ax+b) \bmod p) \bmod m$.
 }
 
-\theorem{The family~$\cal L$ is 1-universal.}
+\theorem{The family~$\cal L$ is 2-universal.}
 
 \proof
 Let $x,y$ be two distinct numbers in $[p]$.
diff --git a/08-string/string.tex b/08-string/string.tex
index b92156c73fb7467cce5711118d78d064593f4a70..a2ccb5e10d6a2717d27d4054864290515ee70863 100644
--- a/08-string/string.tex
+++ b/08-string/string.tex
@@ -20,7 +20,7 @@
 	  are indexed starting with~0.
 	\:$\alpha[i:j]$ is the \em{substring} $\alpha[i]\alpha[i+1]\ldots\alpha[j-1]$;
 	  note that $\alpha[j]$ is the first character \em{behind} the substring,
-	  so we have $|\alpha[i:j]| = j-i$. If $i>j$, the substring is empty.
+	  so we have $|\alpha[i:j]| = j-i$. If $i\ge j$, the substring is empty.
 	  Either $i$ or~$j$ can be omitted, the beginning or the end of~$\alpha$
 	  is used instead.
 	\:$\alpha[{}:j]$ is the \em{prefix} of~$\alpha$ formed by the first~$j$ characters.