Existence of Nonnegative Solutions For a Class of p-Laplacian Equations in IRN
We consider the question of existence of nonnegative solutions of a class of p-Laplacian elliptic problems in the whole space R-N having a sign-changing nonlinearity of the form a (x) g (u).
The interspecific relationships of the main tree species in the forest communities were studied using Fisher's exact test for a 2×2 contingency table, Pearson's correlation coefficient, Spearman's rank correlation coefficient. 1) The number of species_pairs having positive or negative correlation for Spearman's rank correlation coefficient test was higher than that of Pearson's correlation coefficient. Compared with Pearson's correlation coefficient, Spearman's rank correlation coefficient test was more sensitive. 2) Similar ecological adaptability to habitats led to positive correlation between species, and different ecological adaptability resulted in negative correlation, which was proved with environmental interpretation of interspecific relationships. 3) Based on the results, 18 tree species in the communities were divided into four ecological groups, serving as an important theory basis for studying forest structure, function, dynamics and succession.