bio  website  wwwmath.unimuenster.de/u/… 

location  Münster, Germany  
age  26  
visits  member for  4 years, 3 months 
seen  11 hours ago  
stats  profile views  32,179 
PhD student interested in the interactions between algebraic geometry and category theory. More specifically, I "model" algebraic geometry on cocomplete symmetric monoidal categories.
Email: [my last name] [at] unimuenster.de
11h

awarded  Enlightened 
13h

awarded  Nice Answer 
21h

revised 
Universal property of module categories over monads
added 61 characters in body 
1d

revised 
Universal property of module categories over monads
added 941 characters in body 
1d

comment 
Universal property of module categories over monads
Exactly, Tom. My motivation for the terminology "modules" is the example $T=A \otimes $ for some algebra $A$ in a monoidal category, here $T$modules are left $A$modules (not $A$algebras). In my understanding an algebra should carry some sort of associative binary operation, but a $T$action is a morphism $Tx \to x$ satisfying two conditions, which really abstracts the definition of a left module. 
1d

asked  Universal property of module categories over monads 
1d

comment 
Semiring of vector bundles on $\mathbb{C}\mathbb{P}^1$
The condition in the def. of $P$ should be $p = 0 \Rightarrow N \geq 1$, right? 
1d

comment 
Semiring of vector bundles on $\mathbb{C}\mathbb{P}^1$
@Piotr: $H^{1}$ cannot be written like that. I think the normal form is rather $\mathbb{N} \sqcup \{H^p + n : p \in \mathbb{Z} \setminus \{0\}, n \in \mathbb{N}\}$. 
2d

revised 
Semiring of vector bundles on $\mathbb{C}\mathbb{P}^1$
added 212 characters in body 
2d

asked  Semiring of vector bundles on $\mathbb{C}\mathbb{P}^1$ 
Apr 10 
awarded  Popular Question 
Apr 4 
awarded  Taxonomist 
Apr 4 
revised 
Categorification of the integers
added 410 characters in body 
Apr 4 
asked  Categorification of the integers 
Mar 31 
comment 
Analogy between the exterior power and the power set
Meanwhile I've been able to formalize the analogy, using "$\pm$enriched" categories. 
Mar 30 
accepted  Rank vanishing in tensor categories 
Mar 30 
comment 
Rank vanishing in tensor categories
I am interested in char. $0$. If $\mathcal{L}$ is an invertible object, then we don't necessarily have $\mathrm{rk}(\mathcal{L})=1$? In fact, the rank equals the signature of $\mathcal{L}$, which is an involution of $1$, and $1$ is possible e.g. when considering $\mathbb{Z}$graded objects of $\mathcal{C}$ (twisted symmetry). If $X$ is $1_\mathcal{C}$ concentrated in degree $1$, then every dualizable graded object has the form $M=\sum_n M_n \otimes X^{\otimes n}$ with $M_n$ dualizable (almost all $0$), $\mathrm{rk}(X)=1$, hence $\mathrm{rk}(M) = \sum_n (1)^n \mathrm{rk}(M_n)$. Correct? 
Mar 30 
comment 
Rank vanishing in tensor categories
Sorry, forgot to mention that everything is over $\mathbb{Q}$ (as in Deligne, section 7). Now it's included. 
Mar 30 
revised 
Rank vanishing in tensor categories
added 63 characters in body 
Mar 29 
revised 
Rank vanishing in tensor categories
added 60 characters in body 