In section 1 we consider a 3-tuple $S=(|S|,\preccurlyeq,E)$ where $|S|$ is a
finite set, $\preccurlyeq$ a partial ordering on $|S|,$ and $E$ a set of
unordered pairs of distinct members of $|S|,$ and study, as a function of
$n\geq 0,$ the number of maps $\varphi:|S|\to\{1,\dots,n\}$ which are both
isotone with respect to the ordering $\preccurlyeq,$ and have the property that
$\varphi(x)\neq \varphi(y)$ whenever $\{x,y\}\in E.$ We prove a
number-theoretic result about this function, and use it in section 7 to recover
a ring-theoretic identity of G. P. Hochschild.
In section 2 we generalize a result of R. Stanley on the sign-imbalance of
posets in which the lengths of all maximal chains have the same parity.
In sections 3-6 we study the linearization-count and sign-imbalance of a
lexicographic sum of $n$ finite posets $P_i$ $(1\leq i\leq n)$ over an
$n$-element poset $P_0.$ We note how to compute these values from the
corresponding counts for the given posets $P_i,$ and for a lexicographic sum
over $P_0$ of chains of lengths $\mathrm{card}(P_i).$ This makes the behavior
of lexicographic sums of chains over a finite poset $P_0$ of interest, and we
obtain some general results on the linearization-count and sign-imbalance of
these objects.
