Weighted automata (WA) extend finite-state automata by associating with transitions weights
from a semiring S, defining functions from words to S. Recently, cost register automata …

We introduce a subclass of linear recurrence sequences which we call poly-rational
sequences because they are denoted by rational expressions closed under sum and …

We present pum** lemmas for five classes of functions definable by fragments of weighted
automata over the min-plus semiring, the max-plus semiring and the semiring of natural …

Cost register automata (CRA) and its subclass, copyless CRA, were recently proposed by
Alur et al. as a new model for computing functions over strings. We study some structural …

We present three pum** lemmas for three classes of functions definable by fragments of
weighted automata over the min-plus semiring and the semiring of natural numbers. As a …

We give complexity bounds for various classes of functions computed by cost register
automata.

We consider linear cost-register automata (equivalent to weighted automata) over the
semiring of nonnegative rationals, which generalise probabilistic automata. The two …

Cost register automata (CRAs) are deterministic automata with registers taking values from a
fixed semiring. A CRA computes a function from words to values from this semiring. CRAs …

Cost register automata (CRA) are machines reading an input word while computing values
using write-only registers: values from registers are combined using the two operations, as …

In this work we consider two rich subclasses of weighted automata over fields: polynomially
ambiguous weighted automata and copyless cost register automata. Primarily we are …