Complexity theory of

: a field of study shared by mathematics and computer science that is concerned with how the computational complexity of problems increases as the number of cases involved increases and with the classification of the problems according to whether a solution can be found in polynomial time and to the algorithms required
Where does complexity come from?
The approaches that embody concepts of systems, multiple elements, multiple relational regimes, and state spaces might be summarized as implying that complexity arises from the number of distinguishable relational regimes (and their associated state spaces) in a defined system..

Type of computational problem

Where does complexity come from?