Which of the Following Math Classes have you taken?

[Citizen (The) Doctor]

Is game theory considered a mathematical discipline or an application of probability?

[Citizen (The) Doctor]

Is game theory considered a mathematical discipline or an application of probability?

Game theory generally doesn't involve any probability at all. It's an area of applied mathematics most commonly used in economics. The games studied are usually deterministic games where the results depend upon player decisions rather than random chance.

Most of the stuff we studied had to do with mixing and Bayesian equilibria which required some basic probability analysis which is why I framed it in such a way.  Maybe that's only a small part of game theory applications though.