definiens: shall mean, with respect to a TYSABRI Transaction in a Major MarketCountry, the amount(s ) obtained by multiplying ( A ) the Threshold in effect under Section 4.2(d)(i ), ifapplicable, and Section 4.2(d)(ii ) immediately prior to the consummation of such TYSABRITransaction, by ( B ) the Threshold Reduction Fraction applicable to such TYSABRI Transaction;provided, however, that if such TYSABRI Transaction is non - exclusive in such Major Market Country(that is, [COMPANY] Idec or any of its Affiliates will continue to have a right to sell TYSABRI in such MajorMarket Country that is presently exercisable, and not contingent upon the occurrence of some event orthe passage of time, from and after the consummation of such TYSABRI Transaction ), then [COMPANY] Idecshall determine, in good faith and on a reasonable basis ( including the terms and conditions of theTYSABRI Transaction ), the Threshold Reduction Amount in lieu of applying the formula above