York University’s administration is asking the union representing striking workers to agree to binding arbitration to resolve what it says is an impasse over principles that has left 50,000 students out of class for five weeks.

“I would love nothing better than to end this strike, but I cannot compromise the academic excellence and ultimately the long-term learning environment for our students,” Rhonda Lenton, York University’s president, said, explaining why the university is making that move. The window for the semester to be completed is closing, she added. “If we do not end the strike by April 20, we in all likelihood … have to start using the summer as a way to complete [this] term,” she said.

Binding arbitration ended a strike by teaching assistants at the University of Toronto in 2015, and is currently being used to negotiate a new contract between the Ontario Medical Association and the Ontario Ministry of Health and Long-Term Care.

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York and CUPE 3903, the union representing striking instructors, teaching assistants and researchers, are at odds over how many long-serving contract lecturers should be able to receive permanent tenure-track positions. York is the only university in Canada that has a pathway to tenure-track jobs for part-time professors and it has been trying to rein in the “conversion” program in this round of negotiations. The Canadian Union of Public Employees, which represents the striking workers, says the program is essential for countering precarious work in universities.

In the three decades since conversions were introduced, the number of part-timers who were appointed to full-time jobs every year has ranged between one and eight, according to a union document.

York is proposing two conversions a year, while the union has climbed down from 20 to 15 positions a year. That figure is impossible, the president said.

“We have to conclude that we are at impasse,” she said. “Let a third-party binding mediator … find a path between a compromise of principles that not only CUPE 3903 has to live with but the administration, all departments, all faculty will have to live with.”

On Tuesday, the Liberal government was questioned about whether shortfalls in funding contributed to the strike. “For 10 years, since 2008-09, Ontario has had the lowest of all provinces in university funding per student,” said Cindy Forster, the NDP’s labour critic. Grants to universities, colleges and financial aid for students have doubled between 1998 and 2015, but provincial funding has only increased by 30 per cent as enrolment in higher education soared in that time.

This fall, Ontario stepped in to end a five-week college strike and bring hundreds of thousands of students back into the classroom. Mitzie Hunter, Minister of Advanced Education and Skills Development, has said the government will not step in to settle the dispute between York and CUPE 3903.

“We expect all parties to return to the bargaining table to find a solution so that students can return to the classroom to complete their academic year,” a spokesperson said in a statement.

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For students, the issue of conversions is far from their worries about their academic year. Tommy Chang, a second-year student in information technology and an international student, can’t visit his family in Panama because he is waiting to see how many weeks will be added to the term. Next year, he plans to go on a study-abroad program and was hoping to take summer courses to space out his work, but now, everything is up in the air.

“We can’t do anything other than wait even though we pay really high tuition,” Mr. Chang said.

Others are concerned that any delay in their graduation could lead to losing valuable job offers. Hunter Caron, a fourth-year student in design, has an offer for a permanent job at a tech firm in California, but needs to graduate to be eligible to apply for a U.S. employment visa.

“It is really one course that is holding me back from graduating and possibly going to the job that I signed for in November. That is what is most scary for me right now.”