I noticed that proper nouns, such as names of theorems or techniques are often set in italics in scientific writing but not always. Are there rules about it, for example each proper noun should be set in italic the first time it occurs?
A contrived example
There are many different methods for adding two numbers:
Very Simple Addition (VSA) works by calculating
Unnecessary Complicated Addition (UCA) works by calculating
VSA is the method used by everyone but the British who use UCA because of tradition along with their foot-inch based measurement system.