update,

_docs/_layouts/mathjax.html

@@ -0,0 +1,15 @@
+---
+layout: foam
+---
+
+{{ content }}
+
+<script src="https://cdn.jsdelivr.net/npm/mathjax@2/MathJax.js?config=TeX-AMS-MML_HTMLorMML" type="text/javascript"></script>
+<script type="text/x-mathjax-config">
+    MathJax.Hub.Config({
+        tex2jax: {
+            skipTags: ['script', 'noscript', 'style', 'textarea', 'pre'],
+            inlineMath: [['$','$']]
+        }
+    });
+</script>