Unexpected unsatcore

[Former user]

My solution for the Nim exercise (session 5) from the MCS course has a unsat core, which should not be present according to the assistent.

The unsat core is due to line 88 and 91 in the included IDP file.

[Broes De Cat]

IDP is correct. Any atom NB(h, 0, t) can never be true as 0 is not part of the Matches types (1;3;5;7).