I think it depends. In the context of a complex mathematical formula, where you have many intermediate results with very abstract meanings, I think it's more clear to use a single character name than to try to be descriptive with something like: `productOfLuminanceAndDotProductOfSurfaceNormalAndLightDirectionDividedByScatteringConstant`.

I think there are a lot of advantages to abiding by styling conventions and using linters to set a baseline, but there are always exceptions to the rule.