Trace identities for solutions of the wave equation with initial data supported in a ball

Suppose u is the solution of the initial value problem Suppose n ≥ 1 is odd, f and g are supported in a ball B with boundary S, and one of f or g is zero. We derive identities relating the norm of f or g to the norm of the trace of u on S × 0,∞) . These identities are derived using integral geometric and multiplier methods. Copyright © 2005 John Wiley & Sons, Ltd.