The document discusses strategies for coordinating pre-grant and post-grant patent oppositions between the US and European patent systems. It outlines the differences between pre-grant opposition procedures, including third party observations, as well as post-grant procedures such as post-grant review and inter partes review. The document advises that if an application is filed in both the US and Europe, it may be better to initiate a pre-grant opposition in the US first to invoke discovery for prior art, before pursuing a post-grant opposition in Europe.