Error in simplification of symmetrized tensors

[florianwolz]

If one executes the following code manually, one obtains the correct result

Symmetrize(EpsilonGamma({a b p q}), {a b p})
#=> 1/6 * (2 * \gamma_{ab}\gamma_{pq} + 2 * \gamma_{ap}\gamma_{bq} + 2 * \gamma_{aq}\gamma_{bp})

Symmetrize(EpsilonGamma({a p b q}) + EpsilonGamma({a q b p}), {a b p})
#=> 2/3 * (\gamma_{ab}\gamma_{pq} + \gamma_{ap}\gamma_{bq} + \gamma_{aq}\gamma_{bp})

but if one generates the coefficient and symmetrizes

Coefficient(0,0,2,2)
#=> e_1 * \gamma_{ab}\gamma_{pq} + 
        e_2 * (\gamma_{ap}\gamma_{bq} + \gamma_{aq}\gamma_{bp})
Symmetrize(%, {a b p})
#=> (1/6 * e_1 + 2/3 * e_2) * (2 * \gamma_{ab}\gamma_{pq} + 2 * \gamma_{ap}\gamma_{bq} + 2 * \gamma_{aq}\gamma_{bp})

the second term in the brackets is incorrect (since it has to be 2/6 instead of 2/3).