Issue with TensorWedge and TensorReduce?

Bug introduced in 10.0.0 and fixed in 10.3.1

If I use TensorReduce on the result of TensorWedge:

\$Assumptions = {a ∈ Vectors[dim], b ∈ Vectors[dim]};
TensorWedge[a, b]
TensorReduce[%]
TensorReduce[%]


I actually get

a \wedge b
1/2 a \wedge b
1/4 a \wedge b

• A funny bug, this one: Assuming[a ∈ Vectors[n] && b ∈ Vectors[n], Nest[TensorReduce, TensorWedge[a, b], 4]]. – J. M. will be back soon Nov 23 '15 at 17:46
• Seems to be a new bug in version 10 (I tested 10.2). This does not happen in version 9. – Oleksandr R. Nov 23 '15 at 18:34
• This is strange... we're looking into it. Thanks! – Stefan R Nov 25 '15 at 17:44

There was a missing multinomial factor in the transformation rules that TensorReduce has for TensorWedge. This will be fixed in an upcoming version of Mathematica. Thank you for finding it!