This . . . Is a . . . Long . . . Process: A proposed San Francisco public art project by Los Angeles artists Daniel J. Martinez, Renee Petropoulos and Roger F. White will be delayed “an estimated three months to one year” while various city and county officials study its structural elements. The project, which includes four huge steel arches reading “THIS . . . IS A . . . NICE . . . NEIGHBORHOOD,” has already come under fire in San Francisco for its wording, and the new holdups--a series of approvals required because the arches would span the six-lane street fronting Moscone Convention Center--could threaten the project by escalating costs to exceed its $500,000 budget. In a separate series of approvals, the city’s arts commission plans to consider the project’s wording in September.