Are all decidable languages recursively enumerable?

Yes. In particular, recursive (decidable) languages are a subset of the recursively enumerable languages, so anything that’s not recursively enumerable isn’t recursive (decidable).

Are recursively enumerable languages Turing recognizable?

Recursive Enumerable (RE) or Type -0 Language RE languages are also called as Turing recognizable languages.

Are all recursive language recursively enumerable?

Explanation: Every recursive language is recursively enumerable but there exists recursively enumerable languages that are not recursive. If L is accepted by a Non deterministic TM T, and every possible sequence of moves of T causes it to halt, then L is recursive.

Are all languages recursive?

All regular, context-free and context-sensitive languages are recursive.

Which of the following languages is not recursively enumerable?

An example of a language which is not recursively enumerable is the language L of all descriptions of Turing machines which don’t halt on the empty input.

Are recursively enumerable languages countable?

Recursively enumerable languages are countable because TMs are countable. Therefore, recursively enumerable languages ⊂ all languages.

Which of the following is are not true for recursively enumerable language?

Discussion Forum

Que.	Which of the following is/are not true for recursively ennumerable language?
b.	Turing acceptable
c.	Turing Recognizable
d.	None of the mentioned
	Answer:None of the mentioned

What makes a language decidable?

A language is called Decidable or Recursive if there is a Turing machine which accepts and halts on every input string w. A decision problem P is decidable if the language L of all yes instances to P is decidable.

What is the difference between recursive and recursively enumerable languages?

The main difference is that in recursively enumerable language the machine halts for input strings which are in language L. but for input strings which are not in L, it may halt or may not halt. When we come to recursive language it always halt whether it is accepted by the machine or not.

What languages are not recursively enumerable?

Which of the following is not true for recursively enumerable language?

What is meant by enumerable language?

A recursively enumerable language is a recursively enumerable subset in the set of all possible words over the alphabet of the language. A recursively enumerable language is a formal language for which there exists a Turing machine (or other computable function) which will enumerate all valid strings of the language.

What is recursive enumerable (re) language?

Recursive Enumerable (RE) or Type -0 Language RE languages or type-0 languages are generated by type-0 grammars. An RE language can be accepted or recognized by Turing machine which means it will enter into final state for the strings of language and may or may not enter into rejecting state for the strings which are not part of the language.

Are L1 and L2 recursive languages?

Union: If L1 and If L2 are two recursive languages, their union L1∪L2 will also be recursive because if TM halts for L1 and halts for L2, it will also halt for L1∪L2. Concatenation: If L1 and If L2 are two recursive languages, their concatenation L1.L2 will also be recursive.

What is an Rere language?

RE languages or type-0 languages are generated by type-0 grammars. An RE language can be accepted or recognized by Turing machine which means it will enter into final state for the strings of language and may or may not enter into rejecting state for the strings which are not part of the language.

What is Turing machine acceptance of re language?

An RE language can be accepted or recognized by Turing machine which means it will enter into final state for the strings of language and may or may not enter into rejecting state for the strings which are not part of the language. It means TM can loop forever for the strings which are not a part of the language.