Shortest known Erdös chain for William H. Hsu 

3: William Henry Hsu
   Delcher, A., Kasif, S., Goldberg, H., & Hsu, W. H.  (1993).
   Probabilistic Prediction of Protein Secondary Structure Using Causal
   Networks.  In Proceedings of the Eleventh National Conference on
   Artificial Intelligence (AAAI 1993), pp. 316-321.  Washington, DC,
   August 1993.

2: Simon Kasif
   Beigel, R., Alon, N. M, Apaydin, M. S., Fortnow, L. & Kasif, S.  (2001).
   An optimal procedure for gap closing in whole genome shotgun sequencing.
   In Proceedings of the Fifth Annual International Conference on Research
   in Computational Molecular Biology (RECOMB 2001), pp. 22-30.  Montréal,
   CANADA, April 22 - 25, 2001.

1: Alon M. Noga
   Alon, N. M. & Erdo"s, P.  (1985).  An application of graph theory to
   additive number theory.  European Journal of Combinatorics, 6(1985),
   201-203.

0: Paul Erdös

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An Erdös chain of length 4 (my shortest until 2001):

4: William H. Hsu
   A. Delcher, S. Kasif, H. Goldberg, W. Hsu.  Probabilistic Prediction of
   Protein Secondary Structure Using Causal Networks.  In Proceedings of the
   Eleventh National Conference on Artificial Intelligence (AAAI-93), pp.
   316-321.  Washington, DC, August 1993.

3: Arthur L. Delcher
   S. R. Kosaraju and A. L. Delcher. Large-scale assembly of DNA strings
   and space-efficient construction of suffix trees. In Proceedings of the
   Twenty-Seventh Annual ACM Symposium on the Theory of Computing, pages
   169-177, Las Vegas, Nevada, 29 May-1 June 1995.

2: S. Rao Kosaraju
   P. K. Agarwal, A. Aggarwal, B. Aronov, S. R. Kosaraju, B. Schieber, and S.
   Suri, "Computing external farthest neighbors for a simple polygon,"
   Discrete and Applied Mathematics, 31:97-111 (1991).

1: Boris Aronov
   B. Aronov, P. Erdös, W. Goddard, D.J. Kleitman, M. Klugerman, J. Pach,
   and L.J. Schulman, "Crossing families," Combinatorica, 14(2):127-134
   (1994).

0: Paul Erdös

Other known Erdös chains:

4: William Henry Hsu
3: Sylvian Richard Ray
2: Franco P. Preparata
1: Amnon B. Barak
0: Paul Erdös

4: William Henry Hsu
3: Sylvian Richard Ray
2: Franco P. Preparata
1: Douglas B. West
0: Paul Erdös