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+2 votes

There seems to be a bug in Cadabra 1.42 in the unwrap routine for anticommuting objects.
The below is a minimal example that produces it.

{A, B, C}::AntiCommuting.
d{#}::Derivative.
A::Depends(d).
B::Depends(d).

The following produces "-C d{A B}" erroneously. The sign seems to be produced as long as there is at least one anticommuting object inside.

d{A B C}: @unwrap!(%);

If we apply product rule first, this produces "dA B C + A dB C" correctly.

d{A B C}: @prodrule!(%): @unwrap!(%)
asked in Bug reports by (310 points)

2 Answers

+2 votes

Thanks, it's actually a bug in 2.x too... Will fix.

answered by (57.2k points)
+1 vote

Fixed on github master now (finally...).

answered by (57.2k points)
...