fixed error

Makefile

@@ -1,5 +1,5 @@
 pdf: init
-	latexmk < /dev/null
+	latexmk -halt-on-error < /dev/null
 
 clean:
 	latexmk -c

inputs/lecture_20.tex

@@ -208,7 +208,7 @@ we need the following theorem, which we won't prove here:
     then $X^T$ is also a supermartingale,
     and we have $\bE[X_{T \wedge n}] \le  \bE[X_0]$ for all $n$.
     If $(X_n)_n$ is a martingale, then so is $X^T$
-    and $\bE[X_{T \wedge n}] \le  \bE[X_0]$.
+    and $\bE[X_{T \wedge n}] = \bE[X_0]$.
 \end{theorem}
 \begin{proof}
     First, we need to show that $X^T$ is adapted.

wtheo.sty

@@ -24,6 +24,9 @@
 \usepackage{float}
 %\usepackage{algorithmicx}
 
+
+% \font\nullfont=cmr10
+
 \usepackage{pgfplots}
 \pgfplotsset{compat = newest}