#5218 Einhil.dem seems to have index issues

[Richard Gobeli]

The D expression does not simplify.
This is D.
-((5g([],[%1,%2])g([],[%3,%4])g([%1,%4],[],n)g([%3,m],[],%2))/4)+(g([],[%1,%2])g([],[%3,%4])g([%1,n],[],m)g([%3,%4],[],%2))/2-(g([],[%1,%2])g([],[%3,%4])g([%2,m],[],n)g([%3,%4],[],%1))/2+(5g([],[%1,%2])g([],[%3,%4])g([%1,n],[],%4)g([%3,%2],[],m))/4-g([],[%1,%2],%2,m)g([%1,n],[])+g([],[%1,%2],%2,n)g([%1,m],[])

Is this correct? The two terms at the end should cancel due to the symmetry of g and contraction.
It needs to contract g with the derivative indices first, so the derivatives are gone, and then it can use the symmetry of g to cancel them. This term -g([],[%1,%2],%2,m) times g([%1,n],[]) needs to be -g([m,n],[]) otherwise, it becomes -g([],[],m,n), which makes no sense for symmetry.

[Viktor Toth]

In the current version of einhil.dem, declaration of g's symmetry properties is deliberately delayed, precisely to show their relevance to the final result. So the fact that D does not simplify to 0 is a feature, not a bug.