Granular matter: a tentative view

Granular matter describes large collections of small grains, under conditio ns in which the Brownian motion of the grains is negligible (sizes d>1 micr ometer). The grains can exhibit solidlike behavior and fluidlike behavior, but the description of these states is still controversial. The present dis cussion is restricted to static problems, for which the main approach is to describe properly the initial state of each volume element, when it was de posited from a fluid how. [S0034-6861(99)02202-3].