Hello, This is call for reviewers of our paper. We (Mr Hirai and I) have proved by Coq that the balance of Data.Map with the parameters (3,2) can be maintained after insertion and deletion. We are writing a paper about it and have already showed Milan and Simon PJ. Simon suggested us to find those who are interested in our paper on this ML. If someone are interested and kindly volunteer to review it, please tell us. We will tell the URL of our draft. To be precise, we found the exact valid area of the parameters (delta,ratio) not for Adams's scheme but for Nievergelt & Reingold's scheme. The area is very complicated. (3,2) is one and only one integer solution. Also we found ways to produce counter examples which break balance after deletion. Milan kindly did benchmark comparing Adams (4,2), Adams (3,2), and Nievergelt & Reingold (3,2). Performance of insert, delete, lookup, and merge is almost the same. Milan also pointed out that we should prove that the join function can maintain balance. We are now workig on this. Regards, --Kazu