=ADD= =author= Brawley Jr.; Joel V. + Lisonek; Petr =title= Counting Equivalence Classes of Hadamard Pattern Sets by Group Action Methods =number= 92-28 =year= 1992 =sponsor= Austrian Ministery of Science and Research, Austrian Forschungsf"{o}rderungsfonds, project no. P7220. =url= ftp://ftp.risc.uni-linz.ac.at/pub/techreports/1992/92-28.ps.gz =abstract= This paper develops mathematical methods for studying Hadamard pattern sets which are currently used as models of neural networks. Our main result is an explicit isomorphism between the stabilizers of Hadamard patterns and the general linear groups over the finite field GF(2). This isomorphism carries over the respective group actions and can be used as a tool for solving problems related to Hadamard patterns. Two such applications are presented in full detail; specifically, the enumeration of equivalence classes of Hadamard pattern sets and the evaluation of orbit lengths. Most of the Work was done with the aid of CAYLEY, the computer algebra system for group theory =location= 2 =owner= 2 =source= 3 =reftype= 14