Human: I have a question about a branch of mathematics called rule theory. When I say rule theory, you know what I mean, right? Assistant: 
Yes, I do.  Rule theory is a branch of mathematics that studies the properties of rules and their relationships.  It is a very broad field, and there are many different types of rules that can be studied.  For example, there are rules that describe how to perform arithmetic operations, rules that describe how to perform logical operations, rules that describe how to perform operations on strings of characters, and so on.  The study of rules is very important in many areas of mathematics, including computer science, artificial intelligence, and linguistics.