http://www.ams.org/bookstore-getitem/item=MEMO-212-996
Но search this book не работает там (пока что?).
14.06.11 - Update: О! Теперь работает -- на google books можно смотреть внутрь этого дела и искать там (хотя найти что-нибудь удается не всегда).
Но search this book не работает там (пока что?).
14.06.11 - Update: О! Теперь работает -- на google books можно смотреть внутрь этого дела и искать там (хотя найти что-нибудь удается не всегда).
оффтопик
Date: 2011-06-12 01:12 am (UTC)Можете совсем не отвечать на этот вопрос, можете вынести в отдельный пост, как угодно.
Re: оффтопик
Date: 2011-06-12 10:04 am (UTC)У меня нет ни малейшего сочувствия к Буданову, а думать о нем мне нечего. Пусть сторонники военных действий российской армии в Чечне, от Шаманова до Кадырова, о нем думают. Убийство его может стать поводом для неприятных событий, но такой повод всегда можно найти или создать, было бы желание.
no subject
Date: 2011-06-12 01:46 pm (UTC)On-topic
Date: 2011-06-12 02:01 pm (UTC)I have a very stupid question about Koszul(bar-cobar?) duality.
On one hand, of A is an augmented associative algebra, its
dual is RHom_A(k,k) which is the same as RHom_{A\otimes A^{op}}(A,k)
is the centralizer of A--->k that is a terminal object in an appropriate category. On the other hand, this is a universal
pair (B,z) where z is the Maurer-Cartan element of A\otimes B
---- so is the initial object of (slightly different) category.
Of course, I see here no formal contradiction, but have you any
comments about this "dual" description? V. Hinich
Re: On-topic
Date: 2011-06-12 10:27 pm (UTC)I guess I don't yet quite understand the problem. E.g., the functor Ext or RHom between two modules M and N over an algebra A can be defined as Hom from the bar-resolution of M into N, which would make it a terminal object in something. On the other hand, the same Ext is the inductive limit of Hom into N from complexes of A-modules mapping quasi-isomorphically to M, which makes it an initial object in something. Would you view this situation as similar to the one you describe?
To put it bluntly, I'd say any terminal object of any category is at the same time also the initial object of a slightly different category, namely, the opposite category to the first one. If we are to be surprised by such "dual" descriptions, we should better make sure that our situation is distinguishable on some grounds from such a trivial situation with two opposite categories.
no subject
Date: 2011-06-12 10:30 pm (UTC)Re: On-topic
Date: 2011-06-12 11:16 pm (UTC)E.g., if C is a (coassociative, counital) coalgebra, then for any vector space V the tensor product C\otimes V is a cofree comodule, i.e. the terminal object in the category of pairs (left comodule over C, its k-linear map to V). On the other hand, being a tensor product, it is also an initial object in an appropriate category.
Similarly, the cofree conilpotent coalgebra generated by a vector space V is the terminal object in the category of conilpotent coalgebras mapping into V, and at the same time it is just the direct sum of tensor powers of V, which makes it an initial object.
Re: On-topic
Date: 2011-06-13 05:49 am (UTC)I doubt what you say answers my question, but I will think about this.
In the formulation I gave there are no coalgebras - only algebras.
But it is perfectly possible that at the end I will agree that the
question is meaningless.
Thank you anyway.
Re: On-topic
Date: 2011-06-13 09:02 am (UTC)