Two ordered bases B=(βππ)ππ=1 and Bβ²=(βπβ²π)ππ=1 of a vector space π have the same orientation iff the unique linear automorphismπ΄:Bβ¦Bβ² has a positive determinant.
This divides the possible bases of π into two equivalence classes.
An orientation of π is thus a choice of which of these equivalence classes is positive and which is negative.
In terms of a top form
Tip
There is also a characterization in terms of the exterior algebra.