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When I search patents at I see that some patent documents have multiple priority numbers. For example WO2010054132 has 4 priority numbers. (see bibliographic data). What does this mean? Why there is more than 1 priority number?

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up vote 4 down vote accepted

Good question. I am unaware of any limit on the number of documents on which priority may be claimed.

Sometimes a patent application claims priority to an application that itself claims priority to another patent application.

For example, an inventor could file a provisional application. A non-provisional application could claim priority to the provisional. Later, the inventor could file a continuation-in-part that claims priority to both the provisional and non-provisional.

Here, WO2010054132 lists the following priority documents:

12/612,355 04.11.2009 US

61/112,080 06.11.2008 US

12/612,366 04.11.2009 US

12/612,349 04.11.2009 US

It looks like the earliest claim of priority is to a U.S. provisional filed on June 11, 2008. Three separate U.S. non-provisionals were subsequently filed on April 11, 2009.

12/612,366 appears to have been abandoned; the other non-provisionals appear to be pending.

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This is correct. There is no limit. There are some examples of applications claiming priority to more than 100 prior filings. This becomes somewhat confusing. – Dennis Crouch Jan 14 '13 at 20:14

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