On Reduced Products of Kripke Models


Zoran Marković


Ultraproducts of Kripke models for Induitionistic theories were defined by Cleave [1] and Gabbay [2]. In [3] and [4] Gabbay proved the ``Los's theorem'' and some other analogues of classical results. Here we consider the products of Kripke models reduced over arbitrary filters, so called reduced products. Several classes of formulas are defined, for which preservation results are proved. Some preliminary results on this topic were contained in [6].