Monthly Archives: September 2012


Lots of digital cameras come with a default file-naming scheme of IMG_nnnn, where nnnn is a four-digit number assigned sequen­tially, starting with 0001. The four images above are photos I made with four different cameras over a span of more … Continue reading

Posted in uncategorized | 12 Comments

The abc game

Five years ago I wrote about a rumored proof of the abc conjecture, an idea from the 1980s that stands at the juncture between the additive and the multiplicative parts of number theory. Now there’s more abc news, and this … Continue reading

Posted in featured, mathematics | 10 Comments

Stop lights

For something like 80 years, a traffic light was an ordinary incandescent light bulb mounted behind a colored glass lens. Then, in 1999, LED signal lights began appearing at street corners; the light bulb was replaced by an array of … Continue reading

Posted in technology | 7 Comments