Graduate students at Yale and Columbia ended their strike yesterday without receiving the official union recognition they had sought, but leaders still expressed optimism that they had called attention to their cause.

Yale’s Dean of the Graduate School of Arts and Sciences Jon Butler said in an interview yesterday that the school would not grant a union contract to the Graduate Employees and Students Organization (GESO) at Yale.

“Yale’s policy remains as it has been, that Yale considers graduate students to be graduate students,” he said.

Columbia spokeswoman Alissa Kaplan Michaels offered a similar position.

“Our relationship with graduate students is collaborative, rather than employer-employee,” she said.

During the five-day strike last week, many teaching assistants at both schools did not teach their regular classes and instead stood in picket lines or participated in rallies.

While strikers did not secure union recognition, GESO Chair Mary Reynolds still called the action a success, citing the letters of support the union had received from 43 members of the House of Representatives and eight senators. Institutions around the globe, including the European Parliament, also drafted statements asserting their support for graduate student unions, she said.

“One of the goals was to highlight the issues that affect graduate students, and we received national and international media attention,” Reynolds said.

David M. S. Wolach, an organizer for Graduate Student and Employees United (GSEU)—the Columbia union seeking recognition from the University—said the strike “garnered an enormous amount of community support” on Columbia’s campus.

“We felt that we got our message out to the administration that the ball is in their court if they want to avoid strikes in the future,” Wolach added.

University officials and union representatives offered sharply different pictures of the effect of last week’s strike on daily operations at Yale and Columbia.

According to Butler, between 96 and 98 percent of Yale’s discussion sections and language classes taught by graduate students met regularly last week and were taught in the normal fashion. Only 10 to 12 of the school’s several hundred lecture courses were disrupted, he added.

“The strike was minimally evident, both physically and numerically,” Butler said. “It was a very peaceful week.”

Reynolds said that Butler’s figures were “not true.” She said that as many as 450 classes were affected by the strike in some way.

Kaplan Michaels said that, of the approximately 1,270 classes in the Arts and Sciences at Columbia, less than 10 percent were affected.