If I understand correctly, the original formula I had seen:
\frac{\partial}{\partial g^{ab}} ( g^{cd} ) = \frac{1}{2} ( \delta_a^c \delta_b^d + \delta_b^c \delta_a^d)
splits the contribution of the a \ne b derivatives in half to account for Einstein notation summing over them twice.
The...
I'm hoping someone can clarify for me, I have seen the following used:
\frac{\partial}{\partial g^{ab}}\left( g^{cd} \right) = \frac{1}{2} \left( \delta_a^c \delta_b^d + \delta_b^c \delta_a^d\right)
I understand the two half terms are used to account for the symmetry of the metric tensor...