s a list of
<code>n</code> numeric vectors, each of the same length as the
corresponding non-zero vectors in the <code>nb</code>object. These give
the values of the spatial weights for each <code>i</code>-<code>j</code>
neighbour pair. It is often the case that while the neighbours are
symmetric by construction, the weights are not, as for example when
weights are <em>row-standardised</em> by dividing each row of input
weights by the count of neighbours or cardinality of the neighbour set
of <code>i</code>.