I'm wondering why we can't express graph reachability in first order logic in pretty much exactly the same way we express it in second order existential logic. For SOL, one definition is : 1 . L is ...
I was reading the Wikipedia article on Friedman's finite form of Kruskal's tree theorem, and am interested in the large numbers TREE(n). I would like to verify TREE(2)=3 myself, but find conflicting ...