The main theorem states that if K is a finite CW-complex with finite fundamental group G and universal cover homotopy equivalent to a product of spheres X, then G acts smoothly and freely on X×Sn for any n greater than or equal to the dimension of X. If the G-action on the universal cover of K is homologically trivial, then so is the action on X × Sn. Ünlü and Yalçın recently showed that any fi...

of 14 cases who underwent this operation only in one of them because of infection in operation site, we had to extract the expander. also, in the first day of the operation that we injected serum inside the expander of two other patients, the wound opened up and the expander appeared and came out automatically. the remaining ten patients have tolerated the operation after treatment period witho...

abstract one of the basic assumptions in hub covering problems is considering the covering radius as an exogenous parameter which cannot be controlled by the decision maker. practically and in many real world cases with a negligible increase in costs, to increase the covering radii, it is possible to save the costs of establishing additional hub nodes. change in problem parameters during the pl...

Soil microbial communities play a key role in the functioning of terrestrial ecosystems, particular through their interaction with above-ground plants and weathering rocks. In this study, chemical properties diversity soils covered by different organisms on Leshan Giant Buddha body were analyzed. The results showed that concentration soil total organic carbon (TOC), nitrogen (TN) phosphorus (TP...

We investigate the covering problem in RT spaces induced by the RosenbloomTsfasman metric, extending the classical covering problem in Hamming spaces. Some connections between coverings in RT spaces and coverings in Hamming spaces are derived. Several lower and upper bounds are established for the smallest cardinality of a covering code in an RT space, generalizing results by Carnielli, Chen an...

In 1914 Lebesgue defined a ‘universal covering’ to be a convex subset of the plane that contains an isometric copy of any subset of diameter 1. His challenge of finding a universal covering with the least possible area has been addressed by various mathematicians: Pál, Sprague and Hansen have each created a smaller universal covering by removing regions from those known before. However, Hansen’...