BLACK-HOLE AREA IN BRANS-DICKE THEORY

We show that the dynamics of the scalar field phi(x)=''G(-1)(x)'' in B rans-Dicke theories of gravity makes the surface area of the black hol e horizon oscillatory during its dynamical evolution. It explicitly ex plains why the area theorem does not hold in Brans-Dicke theory. Howev er, we show that there exists a certain nondecreasing quantity defined on the event horizon which is proportional to the black hole entropy for the case of stationary solutions in Brans-Dicke theory. Some numer ical simulations are demonstrated for Oppenheimer-Snyder collapse in B rans-Dicke theory.