cleaned up README and ran yarn format

packages/website/README.md

@@ -2,21 +2,24 @@
 
 This website is built using [Docusaurus 2](https://docusaurus.io/), a modern static website generator.
 
-## Build for development and production
+# Build for development
 
-This one actually works without running `yarn` at the monorepo level, but it doesn't hurt. You must at least run it at this package level
+We assume you ran `yarn` at monorepo level.
+
+The website depends on `squiggle-lang`, which you have to build manually.
 
 ```sh
-yarn
+cd ../squiggle-lang
+yarn build
 ```
 
-This command generates static content into the `build` directory and can be served using any static contents hosting service.
+Generate static content, to the `build` directory.
 
 ```sh
 yarn build
 ```
 
-Your local dev server is here, opening up a browser window.
+Open a local dev server
 
 ```sh
 yarn start

packages/website/docs/Internal/Invariants.md

@@ -7,6 +7,8 @@ author:
 abstract: This document outlines some properties about algebraic combinations of distributions. It is meant to facilitate property tests for [Squiggle](https://squiggle-language.com/), an estimation language for forecasters. So far, we are focusing on the means, the standard deviation and the shape of the pdfs.
 ---
 
+_This document right now is normative and aspirational, not a description of the testing that's currently done_.
+
 The academic keyword to search for in relation to this document is "[algebra of random variables](https://wikiless.org/wiki/Algebra_of_random_variables?lang=en)". Squiggle doesn't yet support getting the standard deviation, denoted by $\sigma$, but such support could yet be added.
 
 ## Means and standard deviations
@@ -17,7 +19,8 @@ $$
 mean(f+g) = mean(f) + mean(g)
 $$
 
-$$\sigma(f+g) = \sqrt{\sigma(f)^2 + \sigma(g)^2}
+$$
+\sigma(f+g) = \sqrt{\sigma(f)^2 + \sigma(g)^2}
 $$
 
 In the case of normal distributions,
@@ -28,8 +31,8 @@ $$
 
 ### Subtractions
 
-$$ 
-mean(f-g) = mean(f) - mean(g) 
+$$
+mean(f-g) = mean(f) - mean(g)
 $$
 
 $$