By Shalosh B. Ekhad, Vince Vatter and Doron Zeilberger
Written: Sept. 14, 2005.
Last Update of this page: Oct. 1, 2006.
Note added Oct. 1, 2006: We just found out that this masterpiece was narrow-mindedly rejected by Electronic Research Announcements of the American Mathematical Society. Since editing and refereeing is still done by humans, we decided to forgoe publishing in a "real" journal (even an electronic one), and keep this in our respective websites. You may find it instructive and/or amusing to see the referee's stupid report and our response to it.
Some conjectures are irresistable. Nick Loehr and Greg Warrington told Bruce Sagan, who told Vince Vatter, who told me, that they believe that a certain easy-to-describe set of lattice paths are enumerated by 10**n. Such a simple result must be trivial to prove. And sure it is! So what if it took Vince and I a week to write a Maple program, another two weeks to debug it completely, and Shalosh 5 seconds to find a `grammar' in terms of a family (binary) tree with 81 leaves and 80 internal vertices, and another 30 seconds to prove it rigorously. It sure is trivial, at least a posteriori.
Inspired by our proof, Nick and Greg and Bruce Sagan found a `computer-free' proof (for what it is worth), but, more interestingly, they used their humanized approach to generalize it. Stand by for their forthcoming paper. [Once it is ready we will put a link to it here.]
Added Oct. 23, 2005: I loved Jonas's proof so much that I wrote an expository article about it in my Personal Journal.