Small ι, ο and υ are also rarely used, since they closely resemble the Latin letters i, o and u.
The Bayer designation naming scheme for stars typically uses the first Greek letter, α, for the brightest star in each constellation, and runs through the alphabet before switching to Latin letters.
Some common conventions: The Greek letter forms used in mathematics are often different from those used in Greek-language text: they are designed to be used in isolation, not connected to other letters, and some use variant forms which are not normally used in current Greek typography.
The table below shows a comparison of Greek letters rendered in TeX and HTML.
Note: The empty set symbol ∅ looks similar, but is unrelated to the Greek letter.