PPADcomplete
PPAD-complete is a classification in computational complexity theory used to describe certain problems within the class PPAD (Polynomial Parity Argument, Directed version). PPAD problems are characterized by their roots in fixed-point theorems, such as Brouwer's fixed-point theorem, and are believed to be computationally hard, but not proven to be NP-hard. These problems typically involve finding solutions guaranteed to exist by mathematical theorems but for which efficient algorithms are unknown.
A problem is deemed PPAD-complete if it is both in the PPAD class and as hard as
One prominent example of a PPAD-complete problem is the computation of a Nash equilibrium in a finite
PPAD-completeness helps clarify the computational landscape of problems related to equilibrium computation and fixed points. It
This classification was introduced by Christos Papadimitriou in 1994 and has since become a central concept