functional equations

*To*: mathgroup at smc.vnet.net*Subject*: [mg72014] functional equations*From*: János <janos.lobb at yale.edu>*Date*: Fri, 8 Dec 2006 06:18:04 -0500 (EST)

Ingolf, I lost e-mails from mathgroup from Nov 30, so it is a reply to a post seen on the web. You might want to look the publications of Zoltán Daróczy, who did some work in that area. For example: Z. Daróczy : Über die Funktionalgleichung j [j (x)y]=j (x)j (y) In.: Acta Univ. Debrecen, Ser. Fiz. Chem. 8 (1962), pp. 125-132., MR 32, # 9231 or Z. Daróczy : Az f[x+y f(x)]=f(x)f(y) függvényegyenlet folytonos megoldásáról Hilbert-terekben = Continuous solutions of the functional equation f[x+yf(x)]=f(x)f(y) in Hilbert spaces, (in Hungarian) In.: Mat. Lapok 17 (1966), pp. 339-343., MR 38, # 6267 He co-wrote the classic book Measures of Information and their Characterizations with János Aczél: Z. Daróczy : On Measures of Information and Their Characterizations New York: Academic Press, (1975). (J. Aczél társszerzovel), MR 58 ,# 33509 His home page is at: http://riesz.math.klte.hu/~daroczy/ where if you click on the Laudatio link then you can see some summary by László Székelyhidi in Anglish. With the best, János ---------------------------------------------- Trying to argue with a politician is like lifting up the head of a corpse. (S. Lem: His Master Voice)