arXiv:0902.3370v1 [math.GT] 19 Feb 2009 S 3 L Kh ∗ symp (L) L P Kh ∗,∗ (L) k ∈ Z Kh k symp (L) ∼ =  (i,j ) ∈ Z 2 i − j = k Kh i,j (L), i j J P = i − j j = J