Counting Strings with Given Elementary Symmetric Function
Evaluations II: Circular Strings
Frank Ruskey,
Department of Computer Science,
University of Victoria, Canada.
C. Robert Miers,
Department of Mathematics and Statistics,
University of Victoria, Canada.
Abstract:
Let a be a string over an alphabet that is a finite ring, R.
The k-th elementary symmetric function evaluated at a is
denoted Tk(a).
In a companion paper we studied the properties of
SR ( n;
t1,t2,...,tk ),
the set of of length n strings for which
Ti ( a ) = ti.
Here we consider the set,
LR ( n;
t1,t2,...,tk ),
of equivalence classes under rotation
of aperiodic strings in
SR ( n;
t1,t2,...,tk ),
sometimes called Lyndon words.
General formulae are established, and then refined for the cases
where R is the ring of integers Zq
or the finite field Zq.
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