(logic) Recursion theory. / (computer science) The branch of the theory of computation that studies which problems are computationally solvable using different models.

(mathematics) A branch of mathematics concerned with dynamical systems which suffer sudden qualitative changes from an infinitesimal change in a parameter.

(mathematics) The branch of mathematics dealing with the art of transmitting messages reliably over a noisy channel by adding redundancy to the message.

(mathematics) A branch of mathematics which deals with patterns that inevitably arise in sufficiently large sets (i.e., subsets of some structure).

(logic) A branch of mathematical logic studying computable functions and Turing degrees, concerned with questions such as "What does it mean for a function on the natural numbers to be computable?" and "Can noncomputable functions be classified into a hierarchy based on their level of noncomputability?".

The branch of abstract algebra dealing with group characters.

(mathematics) The branch of mathematics dealing with dynamical systems which can undergo abrupt irreversible qualitative changes due to a tiny change in parameters.

An overall explanation of phenomena in a particular discipline or realm of experience such as economics, sociology, or history.

The branch of mathematics dealing with the algebraic structure of rings.

(physics) The theory that all gross matter is composed of atoms. / (physics) Any of several theories that explain the structure of the atom, and of subatomic particles.