Errors may exist in prior-art documents.
When a potential error is detected, three situations may arise depending on whether the skilled person, using general knowledge,
(i)can immediately see that the document contains an error and immediately identify what the only possible correction should be;
(ii)can immediately see that the document contains an error, but is able to identify more than one possible correction; or
(iii)cannot immediately recognise that an error has occurred.
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 disclosure is taken into account as is.