<正>In this paper .an important property layer-preserving of LF group and an concept LF λ-subgroup generated by LF subset will be introduced. On the height of
This paper deals with the initial boundary value problems for the nonlinear wave equations with varable coefficient principal part.By virtue of compactness uniq
This paper improves Fischer's inequality and Hadamard's inequality as follows:If A=(aij)is either a n×n totally nonnegative metrix with Πi=1^n aii