Abstract-This is an overview of the present-day versions of monadology with some applications to vector lattices and linear inequalities. Two approaches to combining nonstandard set-theoretic models are sketched and illustrated by order convergence, principal projection, and polyhedrality.
DOI: 10.1134/S1990478911030082Keywords: Dedekind complete vector lattice, filter, fragments, principal projection, order convergence, up-down, descent, ascent, polyhedral Lagrange principle, Boolean valued model The notion of monad is central to external set theory. Justifying the simultaneous use of infinitesimals and the technique of descending and ascending in vector lattice theory requires adaptation of monadology for the implementation of filters in Boolean valued universes. This is still a rather uncharted area of research. The two approaches are available now. One is to apply monadology to the descents of objects. The other consists in applying the standard monadology inside the Boolean valued universe V (B) over a complete Boolean algebra B, while ascending and descending by the Escher rules (cp.[1] and [2]).These approaches are sketched and illustrated by tests for order convergence and rules for fragmenting and projecting positive operators in vector lattices. Also, Lagrange's principle is shortly addressed in polyhedral environment with inexact data.