Description: Define a function whose value at j is the semi-infinite set of
contiguous integers starting at j , which we will also call the
upper integers starting at j . Read " ZZ>=M " as "the set
of integers greater than or equal to M ". See uzval for its
value, uzssz for its relationship to ZZ , nnuz and nn0uz for
its relationships to NN and NN0 , and eluz1 and eluz2 for
its membership relations. (Contributed by NM, 5-Sep-2005)