@Override
			public int size() {
				return k;
			}
Return a cursor which lets you iterate over all k-subsets, starting from
the given {@code start} element.

@param start the start element, inclusively
@return a cursor from the given {@code start} element
@throws IllegalArgumentException if {@code start} is not part of
        {@code this} k-subset
jenetics.incubator/src/main/java/io/jenetics/incubator/combinatorial/KSubset.java