Summary: Arrays of numbers may be written not only on a line (= ``a vector'') or in the plain (= ``a matrix'') but also on a circle (= ``a circular vector''), on a torus (= ``a toroidal matrix'') etc. In the latter case, the immanent index-rotation ambiguity converts the standard ``scalar'' product into a binary operation with several interesting properties.
@article{701571,
title = {Circular vectors and toroidal matrices},
booktitle = {Proceedings of the Winter School "Geometry and Physics"},
series = {GDML\_Books},
publisher = {Circolo Matematico di Palermo},
address = {Palermo},
year = {1996},
pages = {[143]-148},
mrnumber = {MR1396609},
zbl = {0847.15012},
url = {http://dml.mathdoc.fr/item/701571}
}
Znojil, M. Circular vectors and toroidal matrices, dans Proceedings of the Winter School "Geometry and Physics", GDML_Books, (1996), pp. [143]-148. http://gdmltest.u-ga.fr/item/701571/