Former Gov. Ed Rendell on Tuesday announced an education-focused forum for Democratic candidates for mayor, with questions drawn up by fourth and fifth graders from the Philadelphia School District.

Could Rendell, who also served two terms as mayor, eventually endorse one of those candidates?

"Not likely," was Rendell's reply, despite an encouraging tweet he sent Doug Oliver's way.

"Doug Oliver deserves a look in the race for mayor. He's a bright, engaging young man with a lot of good ideas. He just might catch on," Rendell tweeted Friday.

Oliver, a former PGW executive and former spokesman for Mayor Nutter, quickly installed Rendell's words on his campaign website.

Rendell on Tuesday said that the tweet was not an endorsement and that he has offered to meet with any candidate for mayor.

Oliver was first to take him up on that, followed by State Sen. Anthony H. Williams, Rendell said.

Former City Councilman Jim Kenney is next up for a meeting, he added.

The Rendell Center for Civics and Civic Engagement at the University of Pennsylvania will host the candidate forum May 4. It will be televised from School District headquarters and viewed in elementary, middle, and high schools across the city.

Rendell said teachers will collect questions from students. The best queries will be posed to the candidates by the students who came up with them.

"We believe that this debate is enormously appropriate because the main emphasis of this campaign will be on education," said Rendell, who founded the center with his wife, Marjorie O. Rendell, a federal appellate judge.

Teachers will be encouraged to use a lesson plan along with the televised forum to get students interested in the election. Rendell said he hopes to generate enthusiasm that students can take home to their parents, spurring them to pay attention to the race and vote in the May 19 primary election.

As for an endorsement, Rendell didn't rule it out but said his personal and professional relationships with the other candidates - former District Attorney Lynne Abraham, former Common Pleas Court Judge Nelson Diaz, Kenney, and Williams - make it a difficult choice.

"I don't have quite the same relationship with Milton," Rendell said of former State Sen. T. Milton Street Sr., who last week survived a legal challenge when a judge denied a request to remove him from the mayoral ballot. That ruling was appealed Monday in the state Commonwealth Court.