Let L₁ be a recursive language. Let L₂ and L₃ be languages that are recursively enumerable but not recursive. Which of the following statements is not necessarily true? A)L₂- L₁ is recursively enumerable B) L₁-L₃ is recursively enumerable C)L₂ intersection L₁ is recursively enumerable D)L₂ union L₁ is recursively enumerable

Question

Quizplus · Accepted Answer

The difference between a recursive language and a recursively enumerable but not recursive language is not guaranteed to be recursively enumerable. This is because while you can enumerate the words in the recursive language, you cannot effectively enumerate the words not in the recursively enumerable language to remove them, making the operation undecidable.

Let L1 Be a Recursive Language

Let L₁ Be a Recursive Language