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1. • CommentRowNumber1.
   • CommentAuthorzskoda
   • CommentTimeJul 21st 2010
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   Author: zskoda
   Format: MarkdownItexOver a [[coring]] there are not only the left and right [[comodules]], but also the left and right [[contramodules]] !

   Over a coring there are not only the left and right comodules, but also the left and right contramodules !

2. • CommentRowNumber2.
   • CommentAuthorDavid_Corfield
   • CommentTimeJul 21st 2010
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   Author: David_Corfield
   Format: MarkdownItexThey cropped up in conversation [here](http://golem.ph.utexas.edu/category/2008/12/the_status_of_coalgebra.html#c023860).

   They cropped up in conversation here.

3. • CommentRowNumber3.
   • CommentAuthorzskoda
   • CommentTimeJul 21st 2010
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   Author: zskoda
   Format: MarkdownItexThe role of [[contramodules]] in the establishing a systematic theory of [[semiinfinite cohomology]] is I think very central for our interests with Urs in mathematical physics. Namely, this is about BRST reduction techniques, especially in the study of mathematics of [[conformal field theory]], [[vertex operator algebras]], free field representations, relations between [[quantum groups]] and [[affine Lie algebras]] and so on.

   The role of contramodules in the establishing a systematic theory of semiinfinite cohomology is I think very central for our interests with Urs in mathematical physics. Namely, this is about BRST reduction techniques, especially in the study of mathematics of conformal field theory, vertex operator algebras, free field representations, relations between quantum groups and affine Lie algebras and so on.