How many three-by-three forms are there?
such that .
By employing the Double Coset Counting Formula we have , and since then such that .
But so , hence, having , this implies that , where .
Then, for with we deduce it is
When bivectors are defined by
so, for two generic covectors
we have the bivector
Cf. this with the data and to construct the famous
So, nobody should be confused about the uses of the symbol dans le calcul vectoriel XD