In this paper I shall look at the application of the ltration technique to omnitemporal logic . The principal result of the paper will be that the system BSeg of [3] has the nite model property; but I shall also make a few remarks about the system B+ of [2].

Following Fine [3], p. 20, we say that a normal propositional modal logic is canonical i all its theorems are valid on the frame of its canonical model . In this paper we prove that K1:1, i.e. S4+ J1 L p) p is not canonical y . We say that two points x and y in a frame are co-accessible i xRy; yRx, but x =6 y. Our proof proceeds by showing that A. The canonical model for K1:1 contains a (...) pair of co-accessible points; and B. J1 is not valid on any frame with a pair of co-accessible points. Clearly our result follows immediately from A and B. (shrink)