The familiar classical result that a continuous map from a space $X$ to a space $Y$ can be defined by giving continuous maps $varphi_U: U to Y$ on each member $U$ of an open cover ${mathfrak C}$ of $X$ such that $varphi_Umid U cap V = varphi_V mid U cap V$ for all $U,V in {mathfrak C}$ was recently shown to have an exact analogue in pointfree topology, and the same was done for the familiar cla...

A knowledge representation and reasoning system must be able to deal with contradictions and revise beliefs. There has been much research in belief revision in the last decade, but this research tends to be either in the Coherence camp (AGM) or the Foundations (TMS) camp with little crossover. Most theoretical postulates on belief revision and belief contraction assume a deductively closed beli...