# Relation of commutators $[A_{\xi},A_{\eta}]$ with the normal bundle


I'm sure I'm missing something obvious here, but I think that the sectional curvature of the ambient should not only be constant, but be identically null. And it seems that a few papers (e.g. this one) use that result.

How can we make that conclusion if the sectional curvature is a non-zero constant?
