In this book, I have the following problem: on page 446, there is a sentence: Note that $(0.9,0.9)$ is not removed by NWBR, as D is not dominated after C is deleted.
I do not understand this "as". Why this condition implies that $(0.9,0.9)$ is not deleted?Can someone kindly go through the definition of Never a weak best response and help me? I also used the definition on page 193 here which might be more clear then that in the book.