lower court, once it accepted the agreement, in revising the specified sentence. In an effort to contradict this conclusion, the defendant asserts that this is a case that involves a mutual mistake of fact; that is, a mutual mistake about a fundamental assumption — the immutability of the guidelines that formed the backdrop against which the parties negotiated the agreed-upon sentence. The doctrine of mutual mistake is recognized in the law of contracts, see 27 Samuel Williston, Williston on Contracts § 70:74 (4th ed.2003), but the attempt to weave it into the fabric of this case is an exercise in futility. Whether a party to a plea agreement may be entitled to relief on the ground of mutual mistake is in dispute. Compare, e.g., United States v. Olesen, 920 F.2d 538, 542 (8th Cir.1990) (<HOLDING>), with, e.g., United States v. Bradley, 381
holding that denial of petition for modification of maintenance was proper when the parties agreement prohibited modification of maintenance holding that principle of mutual mistake does not apply to permit modification of plea agreement holding that mutual mistake as to essential element of plea agreement can invalidate entire agreement holding that where judgment and sentence for nonexistent crime had to be vacated upon remand the state shall have the option of withdrawing from the entire plea agreement since the plea agreement was based on a material mistake of law which works to the benefit of the defendant holding employer statements of policy can give rise to contractual rights without evidence of mutual agreement