What is the notation for the dual field strength in D=11 Five-Brane theory?

[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.

 

[Einj]

Yes, I think that could be correct.

 

[rbwang1225]

ok, thank you!