NEW YORK - Columbia University has asked a judge to reject a student's lawsuit alleging it failed to protect him after a onetime friend called him a "serial rapist" and carried a mattress around campus to protest sexual abuse.

The university said in a federal court filing Friday that Paul Nungesser's lawsuit should be dismissed.

The German citizen sued the university this year, saying it effectively sponsored gender-based harassment and defamation of him.

The university's lawyers permitting Emma Sulkowicz to carry out her mattress-carrying project for class credit, including during commencement activities, was a "decision at the heart of academic freedom."

Nungesser's lawyer says the university "shamefully bowed to social pressure" and turned its back on him.