Implementation
August-26-08
9:18 PM
Pos[a_, b_, c_, d_] :> H[{a, b}, 1] + H[{a, c}, t[b] - 1] + H[{a, d}, -t[a]] + H[{b, c}, 1] + H[{c, d}, t[a]],
Neg[a_, b_, c_, d_] :> H[{a, b}, t[b]] + H[{a, d}, -t[b]] + H[{b, c}, 1] + H[{b, d}, -1 + t[a]] + H[{c, d}, 1],