6 ideas
10163 | Propositional modal logic has been proved to be complete [Kripke, by Feferman/Feferman] |
10760 | With possible worlds, S4 and S5 are sound and complete, but S1-S3 are not even sound [Kripke, by Rossberg] |
16189 | The variable domain approach to quantified modal logic invalidates the Barcan Formula [Kripke, by Simchen] |
15132 | The Barcan formulas fail in models with varying domains [Kripke, by Williamson] |
13007 | Archimedes defined a straight line as the shortest distance between two points [Archimedes, by Leibniz] |
7811 | Sophoclean heroes die terrible deaths when they oppose the new Athenian values [Sophocles, by Grayling] |