Although I have no idea what "matrix product physics" might mean, the problem of rolling a unit sphere (in R^3) along a piecewise smooth path in the plane -- and figuring out its net rotation -- is essentially taking a limit of the product of more and more smaller and smaller matrices . . . and this limit very definitely depends on the path the sphere is rolled along. --Dan Marc wrote: << One more ravelet: seeing path invariance as a kind of symmetry, what form of conservation laws might that imply for a matrix product physics?

...

________________________________________________________________________________________ It goes without saying that .