Is a federal court required to follow the federal Rules of Civil Procedure and procedural due process, which mandate that an expert's report and deposition testimony must be supplemented pretrial, or the expert's testimony must be excluded at trial if the testimony is at variance with the expert's report and deposition testimony, and outside the scope of the expert's report?

question presented is: Is a federal court required to follow the federal Rules of Civil Procedure and procedural due process, which mandate that an expert’s report and deposition testimony must be supplemented pretrial, or the expert’s testimony must be excluded at trial if the testimony is at variance with the expert’s report and deposition testimony, and outside the scope of the expert’s report? 2. In United States v Dunnigan, 507 U.S. 87, 94 (1993), this Court held that “A witness commits perjury if he gives false testimony concerning a material matter with the willful intent to provide false testimony, rather than as a result of confusion, mistake, or faulty memory.” In this context, the Court of Appeals held that given that the witness’s false testimony occurred after he explained that his report contained a factual error, that there was no clear error in the district court’s finding of no perjury. The second question presented is: May a court not find perjury even though a material statement, designed to mislead and influence the jury, was knowingly testified to falsely?