title cannot have latex in it

I forgot - either nbconvert, pandoc, or latex is causing a problem
when I put the greek symbols for alpha-beta in a title.

01_g-h_filter.ipynb

@@ -11,7 +11,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "# The g-h Filter ($\\alpha$-$\\beta$ Filter)"
+    "# The g-h Filter (alpha-beta filter)"
    ]
   },
   {