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3:25 PM
I created . (I first created but immediately changed). Thus it will be suggested by both typing "monoid" or "semigroup" (in coherence with , which encompasses semigroups and monoids which were previously artificially separated).
I also included a tag info.
4:20 PM
3
Q: Automorphisms of Frobenius liftings and degeneration of the Hodge-de Rham spectral sequence

The Thin WhistlerI am still studying Deligne and Illusie's paper (https://eudml.org/doc/143480), and I am again stuck, this time on pages 262/263. Assume $X\longrightarrow S$ is a smooth morphism of $\mathbb{F}_{p}$-schemes, then $\operatorname{Lif}(X,\tilde{S})$ is the gerbe of liftings to $\tilde{S}=S(\mathbb{Z...

0
Q: Pointed versus unpointed maps into a topological monoid

Jeff StromI've just stumbled on something that seems either too good to be true, or else too good for me not to have heard of it before. It has to do with the basepoint forgetting map $$ u: [A, M] \to \langle A, M \rangle, $$ where $A$ is a pointed space, $M$ is a topological monoid, and $\langle A, M\ran...

9
Q: Group completion of topological monoids

Vincenzo ZaccaroLet $M$ be an abelian monoid. For sake of simplicity we shall assume that in $M$ the cancellation law holds true. With this last assumption we define the group completion $G$ of $M$ as $$G:=M\times M/\sim$$ where $(a,b)\sim (a',b')$ if and only if $a+b'=a'+b$. It has been quite surprizing find ou...

0
Q: Is there a Hausdorff space that is also a group such that the group operation is continuous but the inversion map is not continuous?

ZyisThe question is from the definition of to topological group. I can find an example such that the inversion map is continuous but the group operation is not continuous, but I cannot find an example such that the group operation is continuous but the inversion map is not continuous. I guess that su...


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