This is an announcement for the paper “On the numerical index of polyhedral Banach spaces” by Debmalya Sainhttps://arxiv.org/search/math?searchtype=author&query=Sain%2C+D, Kallol Paulhttps://arxiv.org/search/math?searchtype=author&query=Paul%2C+K, Pintu Bhuniahttps://arxiv.org/search/math?searchtype=author&query=Bhunia%2C+P, Santanu Baghttps://arxiv.org/search/math?searchtype=author&query=Bag%2C+S.
Abstract: We present a general method to estimate the numerical index of any finite-dimensional real polyhedral Banach space, by considering the action of only finitely many functionals on the unit sphere of the space. As an application of our study, we explicitly compute the exact numerical index of the family of $3$-dimensional polyhedral Banach spaces whose unit balls are prisms with regular polygons as its base. Our results generalize some of the earlier results regarding the computation of the exact numerical index of certain $2$-dimensional polyhedral Banach spaces having regular polygons as the unit balls. We further estimate the numerical index of two particular families of $3$-dimensional polyhedral Banach spaces.
The paper may be downloaded from the archive by web browser from URL https://arxiv.org/abs/1809.04778