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\newblock Polynomial threshold functions, {$AC^0$} functions and spectral
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\newblock {\em SIAM J. Comput.}, 21(1):33--42, 1992.

\bibitem{Gurv94}
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\newblock Some combinatorial and topological properties of perceptron networks.
\newblock Oral communication at a DIMACS Workshop on Mathematical Theory of
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\bibitem{Lech71}
R.~J. Lechner.
\newblock Harmonic analysis of switching functions.
\newblock In A.~Mukhopadhyay, editor, {\em Recent Development in Switching
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\end{thebibliography}