By Vincent Scully, Catherine Lynn, Erik Vogt, and Paul Goldberger Yale University Press, 2004, 406 pp., paperback $45. How do you judge whether a university is treating its host city decently? Some focus on how much or how little the university does to support the local community through money and programs. Yale University, which has a $12 billion endowment, has won praise in some quarters for operating the New Haven HomeBuyer Program, which has given $15 million — in subsidies of up to $25,000 per household — to help faculty and staff members buy homes in certain neighborhoods.