Last week’s preliminary election in Brockton narrowed the field for mayor to two, with two-term incumbent Linda Balzotti set to face School Committee member and City Hall employee Bill Carpenter. Balzotti and Carpenter outpolled Christopher MacMillan, a Ward 7 city councilor, and retired businessman Ron Matta. School Committee member Timothy Sullivan secured the available Ward 7 seat, defeating Richard Zaccaro and Shirley Asack. In Ward 5, incumbent Dennis DeNapoli will face Ollie Spears in November. A field of 15 candidates for two at-large council seats was winnowed to eight: incumbents Jass Stewart and Robert Sullivan, as well as Shaynah Marie Barnes, Paul L. Beckner, James Daley, Anthony J. Donegan, Craig O. Pina, and Moises Rodrigues.