Useless knowledge #1 "The commonly stated rule, that Easter Day is the first Sunday after the full moon that occurs next after the vernal equinox [first day of spring; explanations in square brackets added by me], is somewhat misleading because it is not a precise statement of the actual ecclesiastical rules. The actual conditions to determine the date for Easter are (1) Easter must be on a Sunday; (2) this Sunday must follow the 14th day of the paschal [Easter] moon; (3) the paschal moon is that of which the 14th day (full moon) falls on or next follows the day of the vernal equinox; and (4) the equinox is fixed in the calendar as March 21. Easter can never occur before March 22 or later than April 25." Easter being a religious feast its date is calculated according to ecclesiastical rules which do not always lead to the same result as the analogous astronomical rules. Everything you never wanted to know on dates and calendars in the calendar FAQ. It also tells you how to calculate the date of the paschal full moon which does not necessary fall on the same day as the astronomical full moon. More information on Easter: origins, meanings and current practice. Unfortunately according to that source the nominal date of the Spring equinox is March 20th which I think is wrong as then Easter could theoretically fall on March 21st which is impossible.

There is no genius without a mixture of madness (Seneca) Or more precise: genius and madness are brothers and sisters. Simon Singh writes a very interesting short essay on John Nash's achievements in game theory in the New Statesman. Apparently the rules for the auctions for the telephone frequencies which raised about 50 billion euro in Germany alone can be derived from Nash's equations. The article ends with a scene from the opening page of Sylvia Nasar's biography A Beautiful Mind which served as the basis for the Oscar awarded movie: a friend visits Nash in the hospital and asks him how he could believe that aliens were recruiting him to save the world and Nash replies: "Because the ideas I had about supernatural beings came to me the same way that my mathematical ideas did. So I took them seriously" (via arts & letters daily). P.S. The comments are back but I am still seriously thinking of moving. I have reserved the Antville name ignorant already. For the time being that address is just used as a clipboard for thoughts and links.

Are you jealous? If you have some spare time (25-30 minutes if you are fast) and stamina you can answer the 65 multiple-choice questions (sorry but this is a serious maybe even scientific exercise) of the Jealousy test. In fact some of those questions consist of several sub-questions so that there are probably close to a 100 questions altogether! My lowest score was a 16/100 in jealous behaviour and my highest was 28/100 concerning dependency issues. I am not really a jealous guy.

Serious stuff

• A paper on how to use compression algorithms like the one used in the famous zip program for author recognition and other classification problems. Claude Shannon's concept of (information) entropy plays a role here. According to Chaitin-Kolmogorov "the entropy of a string of characters is the length (in bits) of the smallest program which produces as output the string" . Zipping programs usually replace often repeated strings of characters, e.g. "the" by a pointer to the last/first occurence of the string. In this way English texts can usually be compressed from 8 bits (one byte) per character to 2 bits per character. The authors (Benedetto, Caglioti and Loreto) of the paper basically suggest to add a part of the unknown text X to several texts T(i) of known authors. The probable author of the unknown text is obtained by minimising the difference in size of the zipped text T(i)+X and the zipped text T(i): Language trees and zipping (via ZEIT-Artikel). And On J. Goodman's comment to "Language trees and zipping".
• ILM: Metal Machine Music - the symphonic tribute on the first live performance of Lou Reed's infamous guitar feedback orgy by the German avant-garde classical ensemble Zeitkratzer at the Berlin MärzMusik festival. I listened to four 20 seconds snippets from this site and was surprised that it did not sound as white noise at all but quite varied. This record must have had a strong influence on anything that Sonic Youth did in the eighties. Another good review here.

No surprise