Questions:

$[5$ points$]$ When we say that a formal language $L$ is "recursive" what type of machine

is needed to check if strings are in L$?$ What is another well$-$known name for this

class of languages?

$[5$ points$]$ When we say that a formal language $L$ is "recursively enumerable" what

type of machine is needed to check if strings are in L$?$ What is another well$-$known

name for this class of languages?

What does it mean when we say $in{A}_{\text{D}\text{F}\text{A}}?$ Specifically, what does $M$

represent? What does w represent? What does $>in{E}_{\text{D}\text{F}\text{A}}ME{Q}_{\text{D}\text{F}\text{A}}M1M2E{Q}_{\text{D}\text{F}\text{A}}LMw$