FEYNMAN IDENTITY - A SPECIAL CASE .1.

There is an identity due to Feynman which relates graphs and closed cu rves on a lattice and it was used by Feynman in his combinatorial proo f of Onsager's closed formula for the partition function of the two-di mensional Ising model, Long ago Sherman considered a special case of t his identity and pointed out similarities with the Witt identity of Li e algebra theory. In this paper and following, Ne revisit this special case and solve some problems related with it. In particular, the weig hts are computed explicitly using paths and words and a direct connect ion with the Witt formula is round. (C) 1997 American Institute of Phy sics.