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Enriched categories, topoi, abelian categories, monoidal categories, homological algebra.

2 votes

Separators in the Category of Groups

A group surjects onto $\mathbb{Z}$ if and only if its abelianization tensored with the rationals is non-trivial.
HJRW's user avatar
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10 votes

What can be the applications of a theory of schemes à la Grothendieck to the category of gro...

The topology you discuss is closely related to the Gromov--Grigorchuk topology on the space of marked groups. You might be interested in this nice paper of Champetier--Guirardel. In recent years, mos …
HJRW's user avatar
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3 votes

Graphs of groups with homomorphisms not necessarily injective

As Yves has already indicated in comments, any "non-injective" graph of groups $\mathcal{G}$ canonically describes a graph of groups $\overline{\mathcal{G}}$ with the usual injectivity hypothesis. I' …
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5 votes

An algebraic approach to the thermodynamic limit $N\rightarrow\infty$?

I doubt the following has anything to do with the thermodynamic limit. However, it has been pointed out that neither the inverse nor the projective limit of a sequence of $\mathbb{Z}/N$'s gives you $ …
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