Is ATM Recognizable? Because we know that ATM is recognizable, our theorem implies that ATM and ATM are both decidable. But we know that ATM is not decidable. This is a contradiction, hence ATM cannot be recognizable. The language ATM and its undecidability Is ATM co Turing? We know that ATM is Turing recognizable, but
Is The Family Of Recursively Enumerable Languages Closed Under Intersection? Recursively enumerable languages are also closed under intersection, concatenation, and Kleene star. Are recursively enumerable languages closed under difference? The class of recursively enumerable languages is not closed under complementation, because there are examples of recursively enumerable languages whose complement is not recursively enumerable. Is