In this paper we study invariant differential operators on manifolds with a given parabolic structure. The model for the parabolic geometry is the quotient of the orthogonal group by a maximal parabolic subgroup corresponding to crossing of the $k$-th simple root of the Dynkin diagram. In particular, invariant differential operators discussed in the paper correspond (in a flat model) to the Dirac operator in several variables.
@article{108029, author = {Peter Franek}, title = {Generalized Verma module homomorphisms in singular character}, journal = {Archivum Mathematicum}, volume = {042}, year = {2006}, pages = {229-240}, zbl = {1164.22310}, mrnumber = {2322409}, language = {en}, url = {http://dml.mathdoc.fr/item/108029} }
Franek, Peter. Generalized Verma module homomorphisms in singular character. Archivum Mathematicum, Tome 042 (2006) pp. 229-240. http://gdmltest.u-ga.fr/item/108029/
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