The elements of judicial estoppel under Texas state law are: (1) a sworn, prior inconsistent statement made in a judicial proceeding; (2) which was successfully maintained in the prior proceeding; (3) not made inadvertently or by mistake, or pursuant to fraud or duress; (4) which is deliberate, clear, and unequivocal. See id. Under applicable federal law, however, the inconsistency sought to be estopped need not arise from a sworn statement. See Andrews, 959 S.W.2d at 650 (citing In re Phillips, 124 B.R. 712, 720 (Bankr. W.D. Tex. 1991)). In the federal arena, judicial estoppel requires only that a party take an affirmative position which it successfully maintained in an earlier proceeding, and which is contrary to the position the party seeks to invoke. See Andrews, 959 S.W.2d at 650. The essential function and justification of judicial estoppel is to prevent the use of intentional self-contradiction as a means of obtaining unfair advantage. See id. The primary purpose of the doctrine is not to protect litigants, but rather the integrity of the judiciary. See id. Thus, judicial estoppel does not require reliance or prejudice before a party may invoke it. See id.