效绵鼎 Non-RE Languages Theorem:there exist languages that are not Recursively Enumerable. Proof outline: the set of all TMs is countable the set of all languages is uncountable the function L:{TMslanguages} cannot be ontoNon-RE Languages Theorem: there exist languages that are not Recursively Enumerable. Proof outline:  the set of all TMs is countable  the set of all languages is uncountable  the function L: {TMs} →{languages} cannot be onto