We plan to update to STACK 4.4, so we tested a bit and found out the following:
cartesian_product({a,c},{b,d})
works fine with STACK Version 2020120600
in tests with STACK version 2023010400 it delivers
The value $B is not of type LIST
Can I do something, or is it a bug in STACK/Maxima ?
Best regards
Frauke