EFFECT OF NITROGEN FERTILIZER ON RICE PHOTOSYNTHATE ALLOCATION AND CARBON INPUT IN PADDY SOIL
European Journal of Soil Science. Blackwell Publishing Ltd. 2019.
Functions defined on metric spaces are studied. For these functions, a generalized Caristi-like condition is introduced. It is shown that this condition is sufficient for a bounded below, lower semicontinuous function to attain its minimum. Criteria for a generalized Caristi-like condition to hold are derived. Generalizations of the Ekeland and Bishop-Phelps variational principles are obtained and compared with their prototypes. © 2019 Society for Industrial and Applied Mathematics Publications. All rights reserved.