16G20 3 minimax equivalence 3 quadratic Tits form 3 15A30 2 15A63 2 15B33 2 16G60 2 the quadratic Tits form 2 (min 1 Hasse diagram 1 Kleiner's poset 1 Tits \(P\)-critical poset 1 \(0\)-balanced subposet 1 \(P\)-critical poset 1 \(inj\)-finite poset 1 category of representations 1 critical poset 1 max)-equivalent posets 1 minimax (semiminimax) sum 1 minimax sum 1 one-side and two-side sums 1 positive definite form 1 positive form 1 principal poset 1 quiver 1 semichain 1 serial poset 1 weak isomorphism 1