小小的改善，亦具有進步性。

在一個高度發展的技術領域，一個小小的改善，亦具有進步性。

http://www.tms.org/pubs/journals/jom/matters/matters-9609.html
Crowded Art: This refers to an area of technology in which there have been a large number of prior inventions. In a crowded art, it takes less of an advancement to obtain a valid patent. Otherwise, one would have to conclude that there can be no further patenting in that art.

http://www.dallasbar.com/members/headnotes_showarticle.asp?article_id=1447&issue_id=131
For example, in Gemtron Corp. v. Saint-Gobain Corp., the District Court for the Western District of Michigan denied summary judgment and found that “KSR does not automatically call for a ruling of invalidity unless the patent challenged is a major development in the art” because even “narrow improvements in a crowded art” continue to be patentable.