diff --git a/morpho_symm/utils/rep_theory_utils.py b/morpho_symm/utils/rep_theory_utils.py
index 3453d94..df67517 100644
--- a/morpho_symm/utils/rep_theory_utils.py
+++ b/morpho_symm/utils/rep_theory_utils.py
@@ -169,7 +169,7 @@ def isotypic_decomp_representation(rep: Representation) -> [Representation]:
     oneline_permutation = np.concatenate(oneline_permutation)
     P_in2iso = permutation_matrix(oneline_permutation)
 
-    Q_iso = rep.change_of_basis_inv @ P_in2iso.T
+    Q_iso = rep.change_of_basis @ P_in2iso.T
     rep_iso_basis = directsum(list(ordered_isotypic_reps.values()),
                               name=rep.name + '-Iso',
                               change_of_basis=Q_iso)