Write a paper for OCaml or ML Workshop (ideally 2025); explain why OCANNL has dimensions units but not axis labels

[lukstafi]

Axis labels are verbose, especially in the einsum notation. Positional representation has a long tradition in mathematics e.g. linear algebra. In shape inference, it's hard, maybe impossible, to come up with a declarative deterministic scheme for inferring axis labels for a shape where dimensions units are not unique (2 or more axes with the same units).