1) The first question seems to tell you why it exists on a convex set in a functional or operation. You can read a book on operational research. It seems that the author of "Operational Research" by Tsinghua Publishing House is Tsinghua University Operational Research Writing Group. .

I don't know what Slater's terms are. I only know the second-order condition. . .

2) This should correspond to the final stationary distribution. Why don't you find another book on advanced algebra and talk about eigenvalues? And look at linear space or something. Recommend Peking University Advanced Algebra. Qiu's version is simpler. If you want knowledge of advanced algebra and linear algebra, it should look easy. .