in this paper, we present some inequalities for the co-pi index involving the some topological indices, the number of vertices and edges, and the maximum degree. after that, we give a result for trees. in addition, we give some inequalities for the largest eigenvalue of the co-pi matrix of g.

in this paper, we introduce the notion of primal strong co-ideals and give some results involving them. it is shown thatsubtractive strong co-ideals are intersection of all primal strong co-ideals that contain them. also we prove that the representation of strong co-ideals as reduced intersections of primal strong co-ideals is unique.

In this work, a new synthesized Y-type zeolite with an Si/Al molar ratio of 2.5 (NaY) was modified with amines, in order to probe the influence of the modification of the adsorbent’s surface on CO2 adsorption. The three selected amines were diethanolamine, tetraethylenepentamine, and 2- methylaminoethanol. The surface nature of NaY was changed after amine modification, which causes a...

This paper studies co-k-plex vertex partitions and more specifically co-2-plex vertex partitions. Co-k-plexes and k-plexes were first introduced in 1978 in the context of social network analysis. However, the study of co-k-plex vertex partitions, or the decomposition of graphs into degree bounded subgraphs, dates back at least to the work of Lovasz in 1966. In this paper, we derive analogues fo...