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Apr 7 |
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What is special about polylogarithms that leads to so many interesting identities and applications?
small improvements/corrections |
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asked | Pull back of D-modules and Koszul resolution |
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Sep 29 |
comment |
Hopf algebra structure on the ring of quasisymmetric functions
Indeed he is. Btw if you are looking for references on the subject, you should know that the product is often called the "stuffle product" (as it is somewhow opposite to the usual "shuffle product" of the Tensor Hopf algebra). |
Sep 10 |
revised |
Can I define the polynomial ring A[x] with an isomorphism f: A ---> A[x]?
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Aug 31 |
revised |
Hopf algebra structure on the ring of quasisymmetric functions
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Aug 31 |
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Hopf algebra structure on the ring of quasisymmetric functions
This is basic duality. Basically if you have a $k$-Hopf algebra $H$ with $k$-basis $h_s$ then $Hom_{k-mod}(H,A) = H^\vee \otimes_k A$. And, by duality, an element $\sum a_s h_s^\vee$ in this last $k$-module corresponds to a $k$-algebra morphism iff it is diagonal. Rather than paraphrasing what I remember about this stuff I added a link to a short simple article on the subject. |
Aug 31 |
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Hopf algebra structure on the ring of quasisymmetric functions
I edited to answer your questions. |
Aug 31 |
revised |
Hopf algebra structure on the ring of quasisymmetric functions
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Aug 31 |
answered | Hopf algebra structure on the ring of quasisymmetric functions |
Aug 29 |
comment |
Iterated Milnor fibrations and Thom's a_f condition
Thanks for the link, I had already glanced at it but I don't think it is relevant since they are only considering a dimension 1 base, i.e. a single function $f:X\to \mathbb C$. |