> an alternative (but mathematically equivalent) graphical notation, which is harder to do computations and write programs in. But this does need to be the cas

> an alternative (but mathematically equivalent) graphical notation, which is harder to do computations and write programs in. But this does need to be the case. Sometimes a graphical notation is a great help. For example, many tensor computations in differential geometry become straightforward using Penrose's graphical notation. Is that the case here? It is difficult to say, as the authors fail to present that notation separately to the results.