There is no single criterion for applying the doctrine of equivalents across borders; there are differences even between European countries, thus the scope of validation of patents stemming from a same European patent may be determined inconsistently by different national courts.
In his latest article, Gaetano Barbaro explores the logical implications of certain requirements that a test should have to assert or deny the presence of infringement in cases where the doctrine of equivalents is applied, and then derives criteria from these requirements to suggest a new test to be used during trials.
