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SeraPhim
  • Member for 4 years, 9 months
  • Last seen this week
  • Leicester, UK
13 votes
2 answers
605 views

Feelings of inadequacy as a PhD mathematician [closed]

6 votes
0 answers
107 views

Contracting homotopies of a projective resolution of $k[x]/(f)$

5 votes
1 answer
276 views

Why is Hochschild cohomology $HH^n(A, A)$ not a functor of $A$?

4 votes
1 answer
124 views

Cyclic cohomology of a field $k$

4 votes
1 answer
254 views

What does "associative up to homotopy" mean for $A_\infty$-algebras?

2 votes
0 answers
177 views

Infinite direct sum of quotient modules

2 votes
1 answer
108 views

Modifying $\frac{\prod_\alpha A_\alpha}{\prod_\alpha B_\alpha}\simeq \prod_\alpha\frac{A_\alpha}{B_\alpha}$ for direct sums

2 votes
3 answers
1k views

Why is the area of a rectangle the height multiplied by the width?

1 vote
1 answer
83 views

Deriving spectral sequence of a filtered complex

1 vote
1 answer
603 views

Trace and higher traces on an algebra

1 vote
1 answer
159 views

Proof that $\text{Hom}_R(M, -)$ is left exact in the category of $R$-modules

1 vote
1 answer
226 views

Uniqueness in the proof of the comparison theorem for injective resolutions

1 vote
1 answer
81 views

Action of the centre on Hochschild cohomology

1 vote
1 answer
118 views

Why does the isomorphism $A^e\otimes_A M\simeq A\otimes_k M$ imply that $A^e\otimes M$ is $A$-projective?

1 vote
0 answers
34 views

Let $U$ be a vector hyperplane. Why does this calculation not find a basis for U?

1 vote
1 answer
17 views

Confusion about representing elements as pure tensors in the definition of the tensor product of dg-algebras

1 vote
3 answers
328 views

Examples of DG-algebras in algebraic geometry, representation theory and abstract algebra

1 vote
1 answer
134 views

Struggling with recovering the associated graded vector space in A User's Guide to Spectral Sequences

1 vote
1 answer
253 views

Kernel of direct sum of module homomorphisms

0 votes
0 answers
36 views

Reference request for the free loop space

0 votes
1 answer
137 views

Boolean rings are associative $\mathbb{Z}/2\mathbb{Z}$-algebras