What types of mistakes cannot be rectified under PCT Rule 91?

Not all mistakes in a PCT application can be rectified under PCT Rule 91. According to MPEP 1836, the following types of mistakes cannot be rectified:

“A mistake shall not be rectifiable under this Rule if: (i) the mistake lies in the omission of one or more entire elements of the international application referred to in Article 3(2) or one or more entire sheets of the international application; (ii) the mistake is in the abstract; (iii) the mistake is in an amendment under Article 19, unless the International Preliminary Examining Authority is competent to authorize the rectification of such mistake under paragraph (b)(iii); or (iv) the mistake is in a priority claim or in a notice correcting or adding a priority claim under Rule 26bis.1(a), where the rectification of the mistake would cause a change in the priority date”

Additionally, the MPEP states that the omission of entire sheets of the international application cannot be rectified under PCT Rule 91. Such corrections may only be made in accordance with PCT Rule 20.6.

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Tags: international application, obvious mistakes, patent procedure, PCT, rectification limitations