We prove a double commutant theorem for separable subalgebras of a wide class
of corona C*-algebras, largely resolving a problem posed by Pedersen. Double
commutant theorems originated with von Neumann, whose seminal result evolved
into an entire field now called von Neumann algebra theory. Voiculescu later
proved a C*-algebraic double commutant theorem for subalgebras of the Calkin
algebra. We prove a similar result for subalgebras of a much more general class
of so-called corona C*-algebras