Singularities of the Projective Dual Variety

We study the singularities of the projective dual variety.Comment: An inaccuracy in the main theorem has been correcte

Comparing the commutative and non-commutative resolutions for determinantal varieties of skew symmetric and symmetric matrices

Let Y be the variety of (skew) symmetric nxn-matrices of rank less than or equal to r. In paper we construct a full faithful embedding between the derived category of a non-commutative resolution of Y, constructed earlier by the authors, and the derived category of the classical Springer resolution of Y.Comment: 16 pages Many typos corrected. Acknowledgement expande