Mary (visited (their cottage with a thatched roof)).
thus the L 1 distance between two words, w 1 and w 2 , can be written as: noting the algebraic equivalence A + B − |A − B| ≡ 2 • min(A, B) and using basic probability theory, we can rewrite the L 1 Norm as follows: min(P(c|w 1 ), P(c|w 2 )) > 0 if and only if c ∈ tP.