The difference between big delta and small delta?

[aCHCa]

Could anybody explain me what's the difference between $\delta\Gamma^{\rho}_{\mu\nu}$ and $\Delta\Gamma^{\rho}_{\mu\nu}$? Thank you

 

[Polyrhythmic]

Could anybody explain me what's the difference between $\delta\Gamma^{\rho}_{\mu\nu}$ and $\Delta\Gamma^{\rho}_{\mu\nu}$? Thank you

The first usually refers to a variation of the quantity, also used in linearized gravity.
The latter is just the Laplacian:

$\Delta=\partial_{\mu}\partial^{\mu}$.