That thesis discusses bispectral invariants on the group of rigid motions. I worked on a recent monograph on the same subject, which could interest you : https:

That thesis discusses bispectral invariants on the group of rigid motions. I worked on a recent monograph on the same subject, which could interest you : https://arxiv.org/pdf/1704.03069.pdf https://arxiv.org/pdf/1704.03069.pdf