A Representation of elements of the Grassmannian space

mnb96
Messages
711
Reaction score
5
Hi,

I am studying some material related to Grassmannians and in particular how to represent k-subspaces of ℝn as "points" in another space.

I think understood the general idea behind the Plücker embedding, however, I recently came across another type of embedding (the "Projection embedding") that sounds more intuitive and simpler to understand (see attached figure for its definition).

Can anyone elaborate a bit more on the main differences between Plücker and Projection embeddings?

In the past I browsed some old textbooks in the classical literature of algebraic geometry, and while the Plücker embedding is always treated extensively, the Projection embedding is not even mentioned at all. Why?
upload_2018-11-5_14-12-3.png
 

Attachments

  • upload_2018-11-5_14-12-3.png
    upload_2018-11-5_14-12-3.png
    49 KB · Views: 720
Physics news on Phys.org
you need to define some of the symbols in your post to make it possible for us to comment. e.g what is X ? if a matrix, how does it represent an element of the grassmannian? also the text you quote contradicts your statement that the projection method is less studied than the plucker one. why not just look at some of the references in [8], which you do not give us.
 
I asked online questions about Proposition 2.1.1: The answer I got is the following: I have some questions about the answer I got. When the person answering says: ##1.## Is the map ##\mathfrak{q}\mapsto \mathfrak{q} A _\mathfrak{p}## from ##A\setminus \mathfrak{p}\to A_\mathfrak{p}##? But I don't understand what the author meant for the rest of the sentence in mathematical notation: ##2.## In the next statement where the author says: How is ##A\to...
The following are taken from the two sources, 1) from this online page and the book An Introduction to Module Theory by: Ibrahim Assem, Flavio U. Coelho. In the Abelian Categories chapter in the module theory text on page 157, right after presenting IV.2.21 Definition, the authors states "Image and coimage may or may not exist, but if they do, then they are unique up to isomorphism (because so are kernels and cokernels). Also in the reference url page above, the authors present two...
When decomposing a representation ##\rho## of a finite group ##G## into irreducible representations, we can find the number of times the representation contains a particular irrep ##\rho_0## through the character inner product $$ \langle \chi, \chi_0\rangle = \frac{1}{|G|} \sum_{g\in G} \chi(g) \chi_0(g)^*$$ where ##\chi## and ##\chi_0## are the characters of ##\rho## and ##\rho_0##, respectively. Since all group elements in the same conjugacy class have the same characters, this may be...
Back
Top