@PetraSchwer thats also not what I said. I said the film is not about math, which is why I think it is wierd to show it at a math and compsci film festival. It features math, but you also wouldnt show "You only live twice" at a Japanese film festival.

@PetraSchwer @ktstiftung its really not a film about math tho. Math very much there is just a narrative and setting device. It was recently shown here in Dresden, at a French film festival, and honestly that made way more sense

@ProfKinyon @OscarCunningham i mean just substract 2 why wouldnt you

@Joemoeller Thats so wild

@jayalane @ngaylinn very avatar jungle episode . i like it

@Joemoeller no i meant cartesian monoidal categories actually. Since you can define groups in them, whereas in monoidal categories you can only define monoids

@Joemoeller i think personally we should call them groupoidal categories. And in this case they should it should be called a groupoidal product.

@Joemoeller maybe the surprising part really is that even tho you can get analogous definitions of everything in the semi-riemannian case, the world is so mich wierder there. And thats also kind of annoying as einstein has been proven right.

@Joemoeller Ok to be honest it is kind of surprising, when one knows that this does not hold in semi-riemannian geometry, namely there are compact non complete semi-riemannian manifolds. Which is wierd.

@Joemoeller I mean the most important part you kind of suppressed, namely that the inner products need to vary smoothly with respect to the metric. Which i think makes the theorem very much expected