Galois Groups of Composed Schubert Problems

Frank Sottile; Robert Williams; Li Ying

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arXiv · 1910.06843

Galois Groups of Composed Schubert Problems

Frank Sottile·Robert Williams·Li Ying

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Abstract

Two Schubert problems on possibly different Grassmannians may be composed to obtain a Schubert problem on a larger Grassmannian whose number of solutions is the product of the numbers of the original problems. This generalizes a construction discovered while classifying Schubert problems on the Grassmannian of 4-planes in C^9 with imprimitive Galois groups. We give an algebraic proof of the product formula. In a number of cases, we show that the Galois group of the composed Schubert problem is a subgroup of a wreath product of the Galois groups of the original problems, and is therefore imprimitive. We also present evidence for a conjecture that all composed Schubert problems have imprimitive Galois groups.

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Frank Sottile, Robert Williams, Li Ying. 2019-10-15. Galois Groups of Composed Schubert Problems. https://arxiv.org/abs/1910.06843

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