Every symbol used across the site, and the conventions it follows. Nothing here should require a reader to guess.
Conventions
Variables are set in italic, operators upright. The differential is an upright following the international convention, not an italic one. A hat denotes an estimate rather than the true value, so is what was calculated and is what is unknown. A tilde means is distributed as. An asterisk marks an optimum.
Anatomy of an expression
One equation from the mean reversion field, annotated. Every convention on this page is visible in it.
Read it as a sentence: the change in the thing equals how fast it is pulled, times how far it currently sits from where it settles, plus a random shove. All five conventions are doing work, and none of them is decoration.