Abstract

We prove that the statement `For all Borel ideals I and J on ωω, every isomorphism between Boolean algebras P(ω)/IP(ω)/I and P(ω)/JP(ω)/J has a continuous representation' is relatively consistent with ZFC. In this model every isomorphism between P(ω)/IP(ω)/I and any other quotient P(ω)/JP(ω)/J over a Borel ideal is trivial for a number of Borel ideals I on ωω. We can also assure that the dominating number is equal to ℵ1\aleph_1 and that 2ℵ1>2ℵ02^{\aleph_1}>2^{\aleph_0}. Therefore the Calkin algebra has outer automorphisms while all automorphisms of P(ω)/FinP(ω)/Fin are trivial. Proofs rely on delicate analysis of names for reals in a countable support iteration of suslin proper forcings.

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