A new characterization of Mehlhorn's polynomial time functionals
Bruce M. Kapron, Stephen A Cook · 2002
A. Cobham (1964) presented a machine-independent characterization of computational feasibility, via inductive definition. R. Constable (1973) was apparently the first to consider the notion of feasibility for type 2 functionals. K. Mehlhorn's (1976) study of feasible reducibilities proceeds from Constable's work. Here, a class of polytime operators is defined, using a generalization of Cobham's definition. The authors provide an affirmative answer to the question of whether there is a natural machine based definition of Mehlhorn's class.>