@ecterrab Thanks for letting me know: sorry I completely blanked on the format! Hopefull thius should work SmallExample.mw This is just an example of Euclidean gravity. The momentum of the h[4,4] field should vanish, but it doesn't vanish for the right reasons in the code. In particular, Eq. 10 is clearly wrong: symbol is a bug that I don't understand; Eq. 11-12 would be fine but Maple doesn't seem to be differentiating indies correctly, since there should be some delta[mu,4]s there but there aren't

@Hullzie16 Hi, here's a short example of 4D Euclidean linearised gravity, where it fails. SmallExample.maple 

@janhardo I appreciate the sentiment, but that code is wrong. By writing coordindates=[t,x1,x2,x3], it has defined four coordinate systems.

@acer Thanks for that, I thought it would just recognise ++ and +=. I'll do some more reading on the compiler: I don't think I considered it being a strict compiler since I've not had any issues in the past.

I've added my MWE in an edit. Alternatively, here (MWE.mw) it is as a worksheet.

From https://www.mapleprimes.com/posts/209047-Minimize-The-Number-Of-Tensor-Components, it appears Maple cannot use identities when reducing the number of components. Maybe this is the issue?

@tomleslie As mentioned by @acer it's a subpackage.
 

Download MWE.mw

This is also the case in Maple 2020 as I have just verified.