b) Erroneous delimitations from the relevant prior art 

In the above-mentioned decision T 11/82 (OJ 1983, 479), the board also held that the (added) delimitations from the relevant prior art should not be incorrect or misleading, otherwise they could indeed alter the subject-matter of the patent. In T 2450/17, the board cited T 11/82, concluding (with reference to T 889/93 and T 1039/93) that remedying this kind of error therefore did not contravene Art. 123(2) EPC.