- radix-n: means the same thing as base-n.
- residue: the answer to the equation a mod n. since there are an infinite number of answers (a+q*n, for any integer q, be it positive or negative), the set of all answers is known as the residue class. the smallest positive answer is known as the common residue.
- a ≡ b (mod n): this is the same thing as saying a mod n = b mod n
- : to translate that into words, 'a is a turing machine that is mapping reducable to a turing machine b'. to turn that into words that actually mean something, 'b can be used to solve a'.