Chen, Jinsheng; van Ditmarsch, Hans; Greco, Giuseppe; Tzimoulis, Apostolos (Wydawnictwo Uniwersytetu Łódzkiego, 2021-07-14)
We introduce a class of neighbourhood frames for graded modal logic embedding Kripke frames into neighbourhood frames. This class of neighbourhood frames is shown to be first-order definable but not modally definable. We ...