updated interference

book.tex

@@ -2440,7 +2440,7 @@ Line 8: $z$ interferes with $w$ and $y$,\\
 Line 9: $z$ interferes with $y$, \\
 Line 10: $t.1$ interferes with $z$, \\
 Line 11: $t.1$ interferes with $z$, \\
-Line 12: $t.2$ interferes with $t.1$, \\
+Line 12: no interference, \\
 Line 13: no interference. \\
 Line 14: no interference.
 \end{quote}