We introduce a new class of sets namely \((1, 2)^\star\)-\(\check{g}_\alpha\)-closed sets, 2)^\star\)-\(\Lambda_{\mathcal{G}}\)-set, 2)^\star\)-\(\lambda_{\mathcal{G}}\)-set and 2)^\star\)-\(\check{g}_\alpha\)-Locally closed are study in bitopological spaces. prove that this classes lies between 2)^\star\)-\(\alpha\)-closed 2)^\star\)-\(\alpha g\)-closed sets. Furthermore, we discuss some essen...

In this paper we prove that if $X $ is a Banach space, then for every lower semi-continuous bounded below function $f, $ there exists a $left(varphi_1, varphi_2right)$-convex function $g, $ with arbitrarily small norm,  such that $f + g $ attains its strong minimum on $X. $ This result extends some of the  well-known varitional principles as that of Ekeland [On the variational principle,  J. Ma...

Based on the theory of frames we introduce a Stone duality for bitopological spaces. The central concept is that of a d-frame, which axiomatises the two open set lattices. Exploring the resulting concept of d-sobriety we find this to be a much more inclusive concept than usual sobriety. Spatial d-frames suggest additional axioms that lead us to define reasonable d-frames; these have an alternat...