1. Nov 22, 2012

### rbwang1225

Hello, I am reading the paper "Covariant Action for a D=11 Five-Brane with the Chiral Field".
I don't understand the $(\partial a)^2$ in the dual field strength $\widetilde{F}_{mn}\equiv\frac{1}{\sqrt {(\partial a)^2}}F^*_{mnl}\partial^la(x)$.
Is it $\partial_ra\partial^ra$?

Regards.

2. Nov 23, 2012

### Einj

Yes, I think that could be correct.

3. Nov 23, 2012

### rbwang1225

ok, thank you!