“…As for twin positive solutions, several studies on boundary value problems different from (E) can be found in [5,14,28,29,30]. Our results not only generalize and extend the known theorems for all the above eigenvalue problems, but also complement the work of many authors [3,15,16,24,33,35,36,38,39,40,41,42], as well as include several other known criteria offered in [1]. The outline of the paper is as follows.…”