Errors may exist in prior-art documents. If, using common general knowledge (see G‑VII, 3.1), the skilled person can
then the errors in the disclosure do not affect its relevance as prior art. The document can thus be considered to contain the correction when assessing its relevance to patentability (see T 591/90).
When a potential error is detected, three situations may arise depending on whether the skilled person, using general knowledge,
When assessing the relevance of a document to patentability,
in case (i), the disclosure is considered to contain the correction;
in case (ii), the disclosure of the passage containing the error is not taken into account;
in case (iii), the literal disclosure is taken into account as is.