Let be a planar Abelian Difference Set and be any Divisor of . Then is a numerical multiplier of , where a multiplier is defined as an automorphism of which takes to a translation of itself for some . If is of the form for relatively prime to the order of , then is called a numerical multiplier.

**References**

Gordon, D. M. ``The Prime Power Conjecture is True for .'' *Electronic J. Combinatorics* **1**, R6 1-7, 1994.
http://www.combinatorics.org/Volume_1/volume1.html#R6.

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1999-05-26