منابع مشابه
Expressibility and Parallel Complexity
It is shown that the time needed by a concurrent read concurrent write parallel random access machine CRAM to check if an input has a certain property is the same as the minimal depth of a rst order inductive de nition of the property This in turn is equal to the number of iterations of a rst order sentence needed to express the property The second contribution of this paper is the introduction...
متن کاملCircuits, Pebbling and Expressibility
We give characterizations of nondeterministic complexity classes such as NP and PSPACE and the classes in the polynomial time hierarchy in the two-person pebble game model [VT89]. These characterizations motivate the definitions of these classes using firstorder sentences extending the results in [Im82]. It is shown that the role-switches resource in the pebble games closely model the levels of...
متن کاملExpressibility in Σ
Inspired by Fagin’s result that NP = Σ 1 , we have developed a partial framework to investigate expressibility inside Σ 1 so as to have a finer look into NP . The framework uses interesting combinatorics derived from second-order EhrenfeuchtFräıssé games and the notion of game types. Some of the results that have been proven within this framework are: (1) for any k, divisibility by k is not exp...
متن کاملExpressibility in Σ 11
Inspired by Fagin’s result that NP = Σ11, we have developed a partial framework to investigate expressibility inside Σ11 so as to have a finer look into NP . The framework uses interesting combinatorics derived from second-order Ehrenfeucht-Fräıssé games and the notion of game types. Some of the results that have been proven within this framework are: (1) for any k, divisibility by k is not exp...
متن کاملExpressibility of Valued Constraints
In this paper we present a project on the expressibility of valued constraints. We recall the result of Cohen et al. [2] which characterises the expressibility of valued constraints in terms of algebraic properties of the constraints. We show why the current algebraic characterisation is rather unsatisfactory and what are the ways we try to explore in order to find a better one.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The Review of Symbolic Logic
سال: 2019
ISSN: 1755-0203,1755-0211
DOI: 10.1017/s1755020318000394