© 2000 by London Mathematical Society
© The London Mathematical Society
Hardy's Uncertainty Principle on Certain Lie Groups
Dipartimento di Matematica, Politecnico di Torino Corso Duca degli Abruzzi 24, 10129 Torino, Italy, astengo{at}calvino.polito.it
School of Mathematics, University of New South Wales Sydney NSW 2052, Australia, m.cowling{at}unsw.edu.au
Dipartimento di Matematica, Università di Roma Tor Vergata via della Ricerca Scientifica 1, 00133 Roma, Italy, diblasio{at}axp.mat.uniroma2.it
PO Box 5978, Jeddah 21432, Saudi Arabia, smadhava{at}memrbksa.com
Received 20 June 1998. Revision received 11 May 1999.
A theorem due to Hardy states that, if f is a function on R such that |f(x)|
C e
|x|2 for all x in R and
for all
in R, where
> 0, ß > 0, and
ß > 1/4, then f = 0. A version of this celebrated theorem is proved for two classes of Lie groups: two-step nilpotent Lie groups and harmonic NA groups, the latter being a generalisation of noncompact rank-1 symmetric spaces. In the first case the group Fourier transformation is considered; in the second case an analogue of the HelgasonFourier transformation for symmetric spaces is considered.