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Plücker Embedding


The Plücker embedding maps the Grassmannian of k-dimensional subspaces of an n-dimensional vector space V over a field K into the projective space of the kth exterior power of V by

 Gr(k,V)∋W=span(v_1,...,v_k)|->[v_1 ^ ... ^ v_k] in P( ^ ^kV).

Changing the basis v_1,...,v_k multiplies the wedge product by the nonzero determinant of the change-of-basis matrix, so the projective point is independent of the chosen basis.

With respect to a basis of V, the homogeneous coordinates of the image are the k×k minors of a matrix whose rows span W. They are called Plücker coordinates, also known as Grassmann coordinates. The image is a closed projective variety of dimension k(n-k) characterized by quadratic Plücker relations. For example, the image of Gr(2,K^4) in P^5(K) is the quadric

 p_(12)p_(34)-p_(13)p_(24)+p_(14)p_(23)=0.

See also

Exterior Algebra, Grassmann Coordinates, Grassmannian, Projective Space, Wedge Product

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References

Harris, J. "Grassmannians and Related Varieties." Lecture 6 in Algebraic Geometry: A First Course. New York: Springer-Verlag, pp. 63-71, 1992.Shafarevich, I. R. Basic Algebraic Geometry, Vol. 1, 2nd ed. Berlin: Springer-Verlag, pp. 42-44, 1994.

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Plücker Embedding

Cite this as:

Weisstein, Eric W. "Plücker Embedding." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/PlueckerEmbedding.html

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