Decision Problems For Turing Machines
نویسندگان
چکیده
We answer two questions posed by Castro and Cucker in [CC89], giving the exact complexities of two decision problems about cardinalities of ω-languages of Turing machines. Firstly, it is D2(Σ 1 1 )-complete to determine whether the ω-language of a given Turing machine is countably infinite, where D2(Σ 1 1 ) is the class of 2-differences of Σ 1 -sets. Secondly, it is Σ 1 -complete to determine whether the ω-language of a given Turing machine is uncountable.
منابع مشابه
Some improvements in fuzzy turing machines
In this paper, we improve some previous definitions of fuzzy-type Turing machines to obtain degrees of accepting and rejecting in a computational manner. We apply a BFS-based search method and some level’s upper bounds to propose a computational process in calculating degrees of accepting and rejecting. Next, we introduce the class of Extended Fuzzy Turing Machines equipped with indeterminacy s...
متن کاملStrong Turing Degrees for Additive BSS RAM's
For the additive real BSS machines using only constants 0 and 1 and order tests we consider the corresponding Turing reducibility and characterize some semidecidable decision problems over the reals. In order to refine, step-by-step, a linear hierarchy of Turing degrees with respect to this model, we define several halting problems for classes of additive machines with different abilities and c...
متن کاملDecision Problems in Group Theory
At the 1976 Oxford Conference, Aanderaa introduced a new class of machines which he called F machines (later renamed as modular machines). Using these he gave two remarkably short and easy examples of finitely presented groups with unsolvable word problem. Both of these examples, together with an exposition of modular machines, will be found in a paper by Aanderaa and Cohen [2]. The aim of this...
متن کاملEXPTIME-complete Decision Problems for Modal and Mixed Specifications
Modal and mixed transition systems are formalisms that allow mixing of overand under-approximation in a single specification. We show EXPTIME-completeness of three fundamental decision problems for such specifications: whether a set of modal or mixed specifications has a common implementation, whether a sole mixed specification has an implementation, and whether all implementations of one mixed...
متن کاملAlgorithmic Problem Complexity
People solve different problems and know that some of them are simple, some are complex and some insoluble. The main goal of this work is to develop a mathematical theory of algorithmic complexity for problems. This theory is aimed at determination of computer abilities in solving different problems and estimation of resources that computers need to do this. Here we build the part of this theor...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Inf. Process. Lett.
دوره 109 شماره
صفحات -
تاریخ انتشار 2009