In the present paper, we have studied MHD free convective two dimensional unsteady viscous incompressible flows through a porous effect bounded by an infinite vertical porous plate with constant suction. The permeability of the porous medium fluctuates in time about a constant mean, and the viscosity of fluid is assumed to vary as a linear function of temperature. The flow is permitted under th...

Taking Mathematica and xThink as representatives of the state of the art in interactive mathematics, we argue conventional mathematical user interfaces leave much to be desired, because they separate the mathematics from the context of the user interface, which remains as unmathematical as ever. We put the usability of such systems into mathematical perspective, and compare the conventional app...

we study the history and recent developments in nonelementarymodel theory focusing on the framework of abstractelementary classes. we discuss the role of syntax and semanticsand the motivation to generalize first order model theory to nonelementaryframeworks and illuminate the study with concrete examplesof classes of models. this second part continues to study the question of catecoricitytrans...