→Higher order terms: Remove Dattani. Definition of process is not inimical to the intellectual content of the article. It add nothing apart from the definition of the term, which generic.
The problem of optimizing higher-order pseudo-boolean functions is generally difficult. The process of reducing a high-order function to a quadratic one is known as "quadratization".<ref name="dattani" />{{cn}} It is always possible to reduce a higher-order function to a quadratic function which is equivalent with respect to the optimisation, problem known as "higher-order [[clique (graph theory)|clique]] reduction" (HOCR), and the result of such reduction can be optimized with QPBO. Generic methods for reduction of arbitrary functions rely on specific substitution rules and in the general case they require the introduction of auxiliary variables.<ref name="fix" /> In practice most terms can be reduced without introducing additional variables, resulting in a simpler optimization problem, and the remaining terms can be reduced exactly, with addition of auxiliary variables, or approximately, without addition of any new variable.<ref name="elc" />
