The BLR linearity test and the low degree test are two common tools in PCPs. By my understanding these tests ensure bounds such that (self-) correctors can be applied. I have two questions regarding the use of both parts:
In the literature those tests are always used to check if e.g. a function is 0.99-'close' to a linear function. What is now exactly meant by 'checking'? Is that approximating the closeness by repeating the test and evaluating the approximation (using Chernoff bounds)?
Are correctors always used in a constructive way? Would it make a difference using them to reject a function that needs to be corrected?