| R. Betti, R.F.C. Walters, The symmetry of the Cauchy completion of a category, Lecture Notes in Math. 962 (1982), 7-12. |
....reversibility defined for enrichments in [Wal82] to two sided enrichments and to the Cauchy completion. Most familiar examples of enrichments over locally partially ordered bicategories (sheaves and group actions) enjoy a nice property of symmetry, called reversibility. As pointed out by Kasangian [BeWal82] a Cauchy completion of a reversible enrichment fails in general to be reversible. This fact forces us to define a completion for reversible enrichments that preserves reversibility. This is the so called Cauchy reversible completion. Thus we get the desired generalisation: an adjoint pair in ....
....on both sides of the inequality that for any a, a # , b#Obj(A) b, a) a # , b) i.e. 1 . Similarly one gets from ( #) 1 that # . 1. There are reversible enrichments with non reversible Cauchy completions. A very simple example (due to S. Kasangian) may be found in [BeWal82]. This motivates the notion of Cauchy reversible completeness defined further. 4.6. Definition. Reversible modules] A # between reversible reversible when it has right adjoint # . 4.7. Remark. If f is a between reversible then the is reversible. 4.8. Definition. ....
R. Betti, R.F.C. Walters, The symmetry of the Cauchy completion of a category, Lecture Notes in Math. 962 (1982), 7-12.
....to introduce the notion of reversibility for bicategories, two2 sided enrichments and Cauchy completion. Most familiar examples of enrichments over locally posetal bicategories (sheaves and group actions) enjoy a nice property of symmetry that we call reversibility. As pointed out by Kasangian [BeWal82] a Cauchy completion of a reversible enrichment fails in general to be reversible. This fact forces us to de ne a completion for reversible enrichments that preserves reversibility. This is the so called Cauchy reversible completion. Thus we get the desired generalisation: an adjoint pair in Caten ....
...., A(a 0 ; a) b2Obj(A) s (b; a) s (a 0 ; b) i.e. 1 s ( s . Similarly one gets from ( s s 1 that 1. There are reversible enrichments with non reversible Cauchy completions. A very simple example (due to S. Kasangian) may be found in [BeWal82]. This motivates the further notion of Cauchy reversible completion. De nition 4.5 (Reversible modules) A V module between reversible V categories is reversible when it has right adjoint s . Remark 4.6 If f is a V functor between reversible V categories then the V module f is ....
R. Betti, R.F.C. Walters, The symmetry of the Cauchy-completion of a category, LNM 962, 82, 7-12.
....get an equivalence of categories IntR : AUnif = DAUnif . The functors ER : AUnif REnr and ERD : DAUnif REnr satisfy ER = ERD IntR . Since ERD is faithfull then also is ER . Recall that the Cauchy completion does not generally preserve reversibility [Be Wal82]. But according to 7.5, one sees that for any uniform 4 uple S, the Cauchy completion of any reversible enrichment over CS is also reversible. Thus from 7.11, one deduces Theorem 9.5 The inclusion functor SC AUnif , AUnif has a left adjoint. Precisely the restriction to the category ....
R. Betti, R.F.C. Walters, The symmetry of the Cauchy-completion of a category, LNM 962, 82, 7-12
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