The UMBRAL TRANSFER-MATRIX METHOD. IV. COUNTING Self-Avoiding Polygons and Walks

By Doron Zeilberger


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Appeared in Elec. J. Comb. v. 8(1) (2001), R28.

Written: March 9, 2001.

This third sequel to the Foundations article in this Umbral Transfer Matrix series , illustrates how to automatically derive Umbral Schemes for 2D self-avoiding polygons and walks, each of whose vertical cross-sections has a bounded number of horizontal edges, but each interval between consecutive horizontal edges can be as long as you wish.


IMPORTANT: This article is accompanied by three Maple packages

USAP, for self-avoiding polygons,

USAW, for self-avoiding walks, and

MAYLIS, for the automatic counting of classes of convex polyominoes by perimeter.

SAMPLE Input and Output Files

If you have package USAP in the same directory as the first input file for USAP: inUSAP1, and type:

maple -q < inUSAP1 > oUSAP1

then, after a few seconds you should get the first output file for USAP.

If you have package USAP in the same directory as the second input file for USAP: inUSAP2, and type:

maple -q < inUSAP2 > oUSAP2

then, after a few days you should get the second output file for USAP.

If you have package USAW in the same directory as the input file for USAW: inUSAW, and type:

maple -q < inUSAW > oUSAW

then, after a few minutes you should get the output file for USAW.

If you have package MAYLIS in the same directory as the first input file for MAYLIS: inMAYLIS1, and type:

maple -q < inMAYLIS1 > oMAYLIS1

then, after a few seconds you should get the first output file for MAYLIS, that gives a fully computer-generated proof to the celebrated Delest-Viennot formula for the number of convex polyominoes of a given perimeter.

If you have package MAYLIS in the same directory as the second input file for MAYLIS: inMAYLIS2, and type:

maple -q < inMAYLIS2 > oMAYLIS2

then, after a few minutes you should get the second output file for MAYLIS, that fully automatically, and rigorously (of course) computes enumerating generating functions for 81 different classes of convex polyominoes by perimeter.


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