How do you know if a set is recursively enumerable?
Table of Contents
How do you know if a set is recursively enumerable?
If A ≤ m B and B is recursively enumerable then A is recursively enumerable. If A ≤ m B and B is not recursively enumerable then A is not recursively enumerable.
Is L’recursively enumerable if L’is also recursive?
If L is recursively enumerable, then L’ is recursively enumerable if and only if L is also recursive. Let L be a language and L’ be its complement. Which one of the following is NOT a viable possibility? Neither L nor L’ is recursively enumerable (r.e.). Both L and L’ are r.e. but not recursive. A) It is possible if L itself is NOT RE.
What is the difference between recursively enumerable and semi-decidable?
Semi-decidable turns out to be equivalent to recursively enumerable in the same way that decidable is equivalent to recursive:-. If you have a Turing machine R that enumerates a recursively enumerable language, you can make a new machine D that takes an input that may or may not be in the language/set.
Is recursively enumerable language closed under complement and set difference?
Recursively enumerable language are closed under Kleene star, concatenation, union, intersection. They are NOT closed under complement or set difference. Let L1 be a recursive language.
Is L1-L3 recursive or not recursive?
A) Always True (Recursively enumerable – Recursive ) is Recursively enumerable B) Not always true L1 – L3 = L1 intersection ( Complement L3 ) L1 is recursive , L3 is recursively enumerable but not recursive Recursively enumerable languages are NOT closed under complement.
What is the difference between Turing-decidable and Turing-recognizable?
A language is Turing-decidable (or decidable) if some Turing machine decides it. Aka Recursive Language. A language is Turing-recognizable if some Turing machine recognizes it. Aka Recursively Enumerable Language.
