Another Proof that Euler Missed: Jonas Sjostrand's Amazingly Simple (and Lovely!) Proof of the No-Longer-So-Amazing Loehr-Warrington Lattice Paths Conjecture

Another Proof that Euler Missed: Jonas Sjöstrand's Amazingly Simple (and Lovely!) Proof of the No-Longer-So-Amazing Loehr-Warrington Lattice Paths Conjecture
By Doron Zeilberger
.pdf .ps .tex

(Exclusively published in the Personal Journal of Shalosh B. Ekhad and Doron Zeilberger)
Written: Oct. 23, 2005.
I have just written to God, and to God's representatives on this earth (Martin Aigner and Günter Ziegler), nominating this lovely proof by Jonas Sjöstrand to be included in the next edition of the book.
The skeptic may want to experiment with the Maple program JONAS implementing the four gorgeous mappings.

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