Tag Archives: expanders

Asymptotic group theory, 3

A Ramanujan graph is a connected finite graph of valency k whose eigenvalues (apart from k and −k) all have modulus at most 2√(k−1). This interval is the spectrum of the infinite k-valent tree T (regarded as an operator on … Continue reading

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Computational algebra in Lisbon

This week I was at a very nice workshop on Computational Algebra in Lisbon. Rarely do I learn so many new things at a conference, although it was only three days in duration. Here are some of the highlights, roughly … Continue reading

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