Theorem RC-5. Quasigroups do not necessarily satisfy RC.

Model. The clauses

C_{4} · A = C_{3} · B C_{2} · A = C_{1} · B C_{4} · F = C_{3} · E C_{2} · F ≠ C_{1} · E

have the following quasigroup model (found by MACE 1.2.0 on gyro at 7.17 seconds).

A:  0             . | 0 1 2 3 4
B:  2             --+----------
C1: 2             0 | 0 1 2 3 4
C2: 1             1 | 1 4 0 2 3
C3: 1             2 | 2 3 1 4 0
C4: 0             3 | 3 0 4 1 2
F:  1             4 | 4 2 3 0 1
E:  0