- #386
matt grime
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But, Doron, an interval (meaning a connected subset of R) is not a singleton set, but that is besides the point. What is a tautology which defines your "interval", I'm not saying it's the only thing defining it, but we've still not seen the proposition which is tautologous. Pick anyone of the objects in your theory. What is the tautology that defines it? Recall a tautology is a proposition.