Tagged Questions

11
votes
1answer
504 views

Analogy between the exterior power and the power set

The symmetric algebra of an object exists in every cocomplete $\otimes$-category. For the category of sets $\mathrm{Sym}(X)$ is the set of multi-subsets of $X$. The usual definiti …
0
votes
1answer
188 views

Domain of the wedge product in Little Spivak

Hello! in Little Spivak, p. 79, we find this: We will therefore define a new product, the wedge product $\omega\wedge\eta\in \Lambda^{k+\ell}(V)$ by $$ \omega\wedge\eta …
4
votes
1answer
211 views

Representation theory for the exterior algebra

Hello everyone. Let $V$ and $W$ be finite dimensional vector spaces over some field $K$. Consider $\rho:Sym(V)\to End(W)$ a homomorphism of algebras with unit (i.e., a representat …
1
vote
0answers
123 views

Non-negative Quadratic forms with Exterior Forms

Hello All, I apologize if the following question is too elementary. Any suggestion is greatly appreciated. Thank you. Let $n\geqslant 4$, $X$ be an $n$-dimensional inner product …
5
votes
1answer
460 views

ANOTHER Exterior differential system on $SO(3;\mathbb R) \times \mathbb R$

I have another exterior differential system for one forms $U^i$, where the $\theta^i$ are a cotangent basis on $SO(3)$, i.e. they satisfy $d \theta^i = \epsilon_{ijk} \theta^j \wed …
0
votes
1answer
185 views

Inequalities Involving Wedge Product (Reference Request)

Hello, I'm looking for references on various inequalities involving the wedge product and exterior forms. The only references I could hunt down are references on Hadamard-Schwarz …
3
votes
1answer
152 views

Decomposability of exterior two-forms

Hello, The following question appears as a step in my proof. It seems easy but somehow I have not been able to prove this. I could solve few special cases though. Any help in thi …
1
vote
1answer
160 views

Exterior differential system on $SO(3;\mathbb R) \times \mathbb R$

I have the following exterior differential system for one forms $\alpha, \beta, \gamma$, where the $\theta^i$ are a cotangent basis on $SO(3)$, i.e. they satisfy $d \theta^i = \eps …
17
votes
6answers
2k views

Is there a preferable convention for defining the wedge product?

There are different conventions for defininig the wedge product $\wedge$. In Kobayashi-Nomizu, there is $\alpha\wedge\beta:=Alt(\alpha\otimes\beta)$, in Spivak, we find $\alpha\we …
7
votes
6answers
754 views

Using Exterior Algebras in combinatorics

As addressed in this past question, there are many applications of linear algebra to combinatorics. What about examples of applications of exterior algebras? Part 4 here is one suc …
6
votes
2answers
307 views

Generalized Grassmannians that parameterize the submodules of a module

I'm looking for something like a Grassmannian, but which parameterizes the submodules of a module rather than the subspaces of a vector space. Most specifically, I'm looking for so …
4
votes
3answers
1k views

n-dimensional “cross product” reference request

I have written a paper which involves a "cross product" in $\mathbb{R}^n$ and I would like to have a reference to point to. Let ${\bf e_1}, \dots, {\bf e_n}$ be the standard basi …
15
votes
11answers
3k views

Geometrical meaning of Grassmann Algebra

I don't understand wedge product and Grassmann algebra. However, I heard that these concepts are obvious when you understand the geometrical intuition behind them. Can you give thi …
10
votes
4answers
616 views

Eliminating 1st order terms in elliptic partial differential equation

Under what conditions is it possible, using a suitable change of variables, to eliminate 1st order terms in an elliptic partial differential equation, so that the equation involves …
4
votes
1answer
633 views

Exterior powers in tensor categories

Let $\mathcal{C}$ be a cocomplete $R$-linear tensor category. Many notions of commutative algebra may be internalized to $\mathcal{C}$. For example an algebra is an object $A$ in …

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