City officials and advocates for the homeless seemed to call a momentary truce on Wednesday as Mayor Bloomberg introduced his new homelessness plan to a standing ovation. Its goals are aggressive: Cut the number of homeless people living in the city’s shelters and streets by 2/3 over the next five years, and build 12,000 units of supportive housing over the next decade.

But those ambitious numbers have left many wondering exactly how it will all be accomplished. While preliminary implementation guidelines won’t be released for another 60 days, the plan is partly designed to fund itself. As the shelter population drops, emergency dollars will go toward preventive services like eviction defense, rental subsidies and family mediation instead.