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Exactness of reduced amalgamated free product C*-algebras

Ken Dykema
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Abstract

Some completely positive maps on reduced amalgamated free products of C*-algebras are constructed; these allow a proof that the class of exact unital C*-algebras is closed under taking reduced amalgamated free products. Consequently, the class of exact discrete groups is closed under taking amalgamated free products.

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Ken Dykema. 1999-11-02. Exactness of reduced amalgamated free product C*-algebras. https://arxiv.org/abs/math/9911001

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