... (4)There is an analogous equation for the second region on the right-hand side of (3), and the last term in (4) also appears in this. As we are considering parity, these termscancel, leaving#2R ... determining the parity of the number of tilings of the region H(m, n) . In any tilingof H(m, n) , one particular domino must always be in place. In Figure 1(b), this is the domino occupying the ... completes the proof since#2H(m, n +1)=#2H(m, n + 1), answering a rmatively the question posed by Early, and giving a combinatorial meaning to the odd factor in #H(m, n) .Analogous to H(m, n) ,...