definiens: means any challenge to the validity or enforceability of any [COMPANY] Patent Right or [COMPANY] Patent Rightin the absence of a breach of this Agreement including, without limitation, by ( a ) filing a declaratory judgment action inwhich any [COMPANY] Patent Right or [COMPANY] Patent Right is alleged to be invalid or unenforceable ; ( b ) citing prior art pursuantto [ * * * ], filing a request for re - examination of any [COMPANY] Patent Right or [COMPANY] Patent Rights pursuant to [ * * * ] orprovoking or becoming party to an interference with an application for any [COMPANY] Patent Right or [COMPANY] Patent Rightpursuant to [ * * * ] ; or ( c ) filing or commencing any reexamination, opposition, cancellation, nullity or similar proceedingsagainst any [COMPANY] Patent Right or [COMPANY] Patent Right in any country