An interesting question posed by Cofman [Atti Accad. Naz. Lincei, (8) 43 (1967)] is the following: ”Let Π be a finite plane with a subset O of points admitting a collineation group G which maps O onto itself and induces a doubly transitive collineation group on the points of O. What can we say about the plane, the set O and the collineation group G?”. A survey about the knowledge on this subjec...

The present study aimed to characterize the effect of a nearby distractor on vertical, horizontal, and oblique saccade curvature under normal saccade preparation times. Consistent with previous findings, longer-latency vertical saccades showed greater curvature away from a distractor than did oblique or horizontal saccades. At short latencies, vertical saccades also showed greater curvature tow...

We study the $f(R,T)$ cosmological models under self-similarity hypothesis. determine exact form that each physical and geometrical quantity may take in order Field Equations (FE) admit self-similar solutions through matter collineation approach. two models: case$\ f(R,T)=f_{1}(R)+f_{2}(T)$ case $f(R,T)=f_{1}(R)+f_{2} (R)f_{3}(T)$. In case, we state general theorems which completely of unknown ...

Involving the Ricci curvature and the squared mean curvature, we obtain basic inequalities for different kind of submaniforlds of a Sasakian space form tangent to the structure vector field of the ambient manifold. Contrary to already known results, we find a different necessary and sufficient condition for the equality for Ricci curvature of C-totally real submanifolds of a Sasakian space form...