typesetting notes and gotcha

[shensquared]

• when using {: . } for class definition, line break matters. If we want to keep everything under the "blob", we need to use <br> tag instead of a natural line break and it's so tedious...
  need to improve.
• single dollar sign vs double dollar signs needs manual/careful setting-up;
  need to automate this.
• conditional probability type setting is finicky. sometimes we need to do $\mathbb{P}(X_j\|Y)$ instead of $\mathbb{P}(X_j|Y)$ to get $\mathbb{P}(X_j|Y)$-- note the \| Obviously having to do with escaping char but not sure of the root cause of it.
  need to really understand it before attempting a fix.