Now showing items 1-7 of 7

    • A parameterized halting problem, the linear time hierarchy, and the MRDP theorem 

      Chen, Yijia; Muller, Moritz Martin; Yokoyama, Keita (Association for Computing Machinery (ACM), 2018)
      Conference report
      Open Access
      The complexity of the parameterized halting problem for nondeterministic Turing machines p-Halt is known to be related to the question of whether there are logics capturing various complexity classes [10]. Among others, ...
    • A remark on pseudo proof systems and hard instances of the satisfiability problem 

      Maly, Jan; Muller, Moritz Martin (2018-11-20)
      Article
      Open Access
      We link two concepts from the literature, namely hard sequences for the satisfiability problem sat and so-called pseudo proof systems proposed for study by Krajícek. Pseudo proof systems are elements of a particular ...
    • Automating resolution is NP-Hard 

      Atserias, Albert; Muller, Moritz Martin (2020-09)
      Article
      Open Access
      We show that the problem of finding a Resolution refutation that is at most polynomially longer than a shortest one is NP-hard. In the parlance of proof complexity, Resolution is not automatable unless P = NP. Indeed, we ...
    • Automating Resolution is NP-hard 

      Atserias, Albert; Muller, Moritz Martin (Institute of Electrical and Electronics Engineers (IEEE), 2019)
      Conference report
      Open Access
      We show that the problem of finding a Resolution refutation that is at most polynomially longer than a shortest one is NP-hard. In the parlance of proof complexity, Resolution is not automatizable unless P = NP. Indeed, ...
    • Feasibly constructive proofs of succinct weak circuit lower bounds 

      Muller, Moritz Martin; Pich, Ján (2020-02)
      Article
      Open Access
      We ask for feasibly constructive proofs of known circuit lower bounds for explicit functions on bit strings of length n. In 1995 Razborov showed that many can be proved in PV1, a bounded arithmetic formalizing polynomial ...
    • Polynomial time ultrapowers and the consistency of circuit lower bounds 

      Bydžovský, Jan; Muller, Moritz Martin (2020)
      Article
      Open Access
      A polynomial time ultrapower is a structure given by the set of polynomial time computable functions modulo some ultrafilter. They model the universal theory ∀PV of all polynomial time functions. Generalizing a theorem of ...
    • The parameterized space complexity of model-checking bounded variable first-order logic 

      Chen, Yijia; Elberfeld, Michael; Muller, Moritz Martin (2019)
      Article
      Open Access
      The parameterized model-checking problem for a class of first-order sentences (queries) asks to decide whether a given sentence from the class holds true in a given relational structure (database); the parameter is the ...