NEW YORK » Aided by four friends, and to the cheers of some of her classmates, the student who protested Columbia University’s handling of her sexual assault complaint by carrying a mattress around campus all year hoisted it for the last time Tuesday as she crossed the stage at a graduation ceremony.

Up until seconds before the student, Emma Sulkowicz, walked onstage, Columbia officials had asked her to leave the mattress behind. President Lee C. Bollinger turned away as she crossed in front of him, failing to shake her hand, as he did with the other graduates.

Sulkowicz’s graduation, and the end of her protest, brought to a close a tumultuous year, in which Columbia became a focus of the movement to change how universities address sexual assault.

A student group called No Red Tape has held protests, including one in which it projected the words "Columbia protects rapists" on the facade of a school library, and a number of students on Tuesday put red tape on their baby-blue mortarboards to show their support. In February, the university instituted a sexual respect education requirement, which obliges students in all schools to attend workshops or complete art projects on the theme of sexual respect.

As a result of her protest, which is also her senior art thesis, Sulkowicz herself has become the face of a national movement to raise awareness about sexual assault.

She attended the State of the Union address this year as the guest of Sen. Kirsten E. Gillibrand, D-N.Y., who is pushing a bill that would require every college to survey its students about their experience with sexual violence, create a uniform disciplinary process for accusations of assault and give law enforcement agencies a greater role.

Minutes before Sulkowicz walked across the stage, Paul Nungesser, the student she has accused of rape, did so as well, to little response from the crowd.

Nungesser, who was cleared by the university and has maintained that their sexual encounter was consensual, filed a federal discrimination suit last month against the school, Bollinger and the professor who approved Sulkowicz’s thesis project, saying he has been the victim of a harassment campaign.

One of the rules Sulkowicz set for her project was that she would carry the mattress whenever she was on campus until Nungesser was no longer there.

The ceremony on Tuesday was on Class Day for seniors at Columbia College. The universitywide commencement is Wednesday, but Sulkowicz said Tuesday she was done with her project.

As for what will become of the mattress, which she bought online, she said she would hang onto it.

"If some sort of museum wants to buy it, then I’m open to that," she said, "but I’m not going to just throw it away."

Nungesser, who walked briskly away from campus immediately after the ceremony, declined to comment.

The university had actively discouraged Sulkowicz from carrying the mattress. In an email sent to students Monday, the university asked students not to bring "large objects which could interfere with the proceedings or create discomfort to others in close, crowded spaces shared by thousands of people" into the ceremonial area.

Sulkowicz said that as students were lined up before the ceremony in Alfred Lerner Hall, a woman approached her and asked her to put the mattress in a room in the hall for the duration of the ceremony. Sulkowicz, who had stated she would not walk in the ceremony if she could not carry the mattress, refused.

Later, as Sulkowicz and her friends approached the stage, the woman reappeared and again asked her not to take it onstage, saying it would "block the flow of traffic."

Even the dean who was reading out the names seemed to get nervous, stumbling over hers.

As Sulkowicz and her friends ascended the stage, Bollinger, who had been shaking the students’ hands, turned his back and leaned down as though to pick something up from his seat. Sulkowicz leaned over the mattress, trying to catch his eye, then straightened up and kept walking, shrugging with her free hand.

"I even tried to smile at him or look him in the eye, and he completely turned away," she said later. "So that was surprising, because I thought he was supposed to shake all of our hands."

A spokeswoman for the university, Victoria Benitez, said the mattress had been between Sulkowicz and Bollinger and no snub was intended.

However, the keynote speaker, Mayor Eric Garcetti of Los Angeles, alluded approvingly to Sulkowicz’s protest. Applauding student activism at Columbia, he told the students: "You felt outside of society, sufficiently determined to challenge hierarchy that you took risks. You held contrary opinions, held die-ins and sit-ins and carried mattresses. Most importantly, you have learned to empathize, to look out for others and to listen."

© 2015 The New York Times Company