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3 votes
1 answer
263 views

Cohomology of commutative monoid acting on module

I have a some naive questions about how to define the cohomology of a commutative monoid. One way to express the cohomology of a group $G$ with coefficients in a module $A$ is as $\text{Ext}^i_{\...
xir's user avatar
  • 2,044
1 vote
0 answers
69 views

How exactly to adapt Brown's collapse from monoids to algebras?

In The Geometry of Rewriting Systems (Springerlink behind paywall), Kenneth Brown describes a method to collapse the bar resolution of a monoid. Roughly: Given a simplicial set $X$ equipped with a ...
Hilario Fernandes's user avatar
1 vote
0 answers
202 views

What is the normalized complex of a simplicial set with a monoid action?

This question is a follow up to this question I posted on Math.SE. I will make this question self-contained, though. In a certain point on the paper The Geometry of Rewriting Systems, Kenneth Brown ...
Hilario Fernandes's user avatar
2 votes
0 answers
63 views

QF-3 monoid algebras

A finite dimensional algebra $A$ is called QF-3 in case the injective envelope of the regular module is projective. For example all Frobenius algebras are QF-3. Given a monoid algebra $kG$ of a finite ...
Mare's user avatar
  • 26.5k
5 votes
0 answers
395 views

Derived tensor products and Tor of commutative monoids

Two commutative monoids $M,N$ have a tensor product $M\otimes N$ satisfying the universal property that there is a tensor-Hom adjunction for any other commutative monoid $L$: $$\text{Hom}(M\otimes N,L)...
John Berman's user avatar
5 votes
1 answer
383 views

Projective resolutions for commutative monoids

What is the right notion of a projective resolution of a commutative monoid? The category Mon of commutative monoids has plenty of projective (and even free) objects. Indeed, for every set $X$ one ...
Hannes Thiel's user avatar
  • 3,497
5 votes
1 answer
304 views

flat maps of monoids which are not localizations

It is well known that a localization $S^{-1}R$ of a commutative ring $R$ is flat as a $R$-module. Rather, I am looking for extensions of rings which share certain properties of localizations, like ...
Ricardo Andrade's user avatar
27 votes
13 answers
4k views

Homological algebra for commutative monoids?

Homological algebra for abelian groups is a standard tool in many fields of mathematics. How much carries over to the setting of commutative monoids (with unit)? It seems like there is a notion of ...
Chris Schommer-Pries's user avatar