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Feb
8
revised Cominuscule property of nilpotent orbits
fixed mini -> minu and the link
Feb
1
comment product of root multiplicities in Kac Moody Algebras
Trivial comment: the Lie bracket goes from $\mathfrak g \otimes \mathfrak g \to \mathfrak g$, so your appeal to "tensor products of $\mathfrak g$" is not completely unreasonable.
Feb
1
comment What is… A Grossone?
And "Ancient Italian grossones are linguistically close to Sergeyev’s grossone but differ in value."
Jan
31
answered Degree of quasi-projective variety
Jan
23
comment Reference for the notion of polyhedra “degenerations”
I have certainly heard this phrase "coarsening of the normal fan". Another phrase to look for is "Minkowski summand", e.g. of the Chow polytope in the Gr\"obner polytope. The example I've seen people pursue is "pseudo-Weyl polytopes", degenerations of $hull(W\cdot \lambda)$ where $\lambda$ is a regular dominant weight for a Weyl group $W$. (Those have more degenerations than just $\lambda$ nonregular.)
Jan
10
awarded  Nice Answer
Jan
9
answered Locked convex polyhedra
Jan
8
awarded  lie-algebras
Jan
7
answered Is there a formula for the Frobenius-Schur indicator of a rep of a Lie group?
Jan
4
comment Algebraic independance of exponentials
You should perhaps skip one of your current tags in favor of "reference-request" (you can only have 5 tags total).
Dec
30
comment If the restriction of a vector bundle to a divisor is semi stable, then is the vector bundle itself semistable?
What's happening here if $X$ is a high genus curve?
Dec
29
comment Equivariant Cohomology of flag varieties
The natural action is of $W$ on the right of $G/T$, not $G/B$, but they're homotopic and so have the same cohomology. If that's what you want, then as a $W$-module it's the regular representation. This is proved in e.g. Humphreys' gray book on Coxeter groups, by a Galois theory argument.
Dec
22
comment Manifolds as simultaneous coset spaces
Do you want $G$ to be finite-dimensional? If not, I suspect that the condition is simply that $X$ be a fiber bundle over $Y$, with $G$ the group of diffeomorphisms of $X$ taking fibers to fibers.
Dec
20
answered Is there a short proof that the Kostka number $K_{\lambda \mu}$ is non-zero whenever $\lambda$ dominates $\mu$?
Dec
15
comment Grobner basis for a general algebra
Kreuzer, Martin(D-DORT); Robbiano, Lorenzo(I-GENO) Computational commutative algebra. 2, or, Ene, Viviana; Herzog, Jürgen Gröbner bases in commutative algebra
Dec
14
comment Grobner basis for a general algebra
Since you're asking about subalgebras, these are SAGBI bases, not Gr\"obner bases. I don't know the counterexamples offhand that say that subalgebras may not have finite SAGBI bases, but believe they are known.
Dec
14
answered Applications of Representation Theory in Combinatorics
Dec
14
comment Applications of Representation Theory in Combinatorics
What representation-theoretical reason do you have for Schubert structure constants on full flag manifolds to be nonnegative? I know them if you change the first part to "geometric" or second to "Grassmannian".
Dec
12
comment Sophisticated treatments of topics in school mathematics
Note that Dehn invented it a long time before abstract tensor products were defined!
Dec
7
comment Pedagogical question on Lie groups vs. matrix Lie groups
Why a finite cover, Ben? The two examples I think about are $\widetilde{SL_2(\mathbb R)}$, and $\{ \begin{pmatrix} 1&a&z\\&1&b\\&&1\end{pmatrix} \ :\ a,b,z \in \mathbb R \} \big/ \langle z \in \mathbb Z\rangle$. I can't see much benefit in an introductory course in including non-matrix groups.