Matthew wrote:

> John:

> I think you have a typo in post #13. You mean \$$\check{G}\$$ not \$$\hat{G}\$$, right?

Right, sorry. I've gone back and fixed that - I hope Simon doesn't get upset.

> You said in Lecture 65 that \$$\hat{F}\$$ is the **companion** of \$$F\$$ while \$$\check{F}\$$ is the **conjoint** of \$$F\$$.

Right. I always mix up "vee" and "wedge" when typing in LaTeX, and apparently I mix up "hat" and "check" too. I seem to do bad at all these arbitrary binary conventions.