  We examine the problem of searching sequentially for a desired real value (a
key) within a sorted unbalanced three-dimensional finite real array. This
classic problem can be viewed as determining the correct dimensional threshold
function from a finite class of such functions within the array, based on
sequential queries that take the form of point samples. This note addresses the
challenge of constructing algorithms that require the minimum number of queries
necessary in the worst case, to search for a given key in arrays that have
three dimensions with sizes that are not necessarily equal.
