KATHERINE O. MULLER Katherine O. MULLER, widow of Carl MULLER, died on Tuesday at her home, 1419 Seventy-seventh street. She was born in Bavaria fifty-six years ago and had been a resident of Brooklyn fifteen years. She is survived by four sons, Frank, a purchasing agent for the E.W. Bliss Company; Grover, a sergeant mechanic in the U.S. Aviation Service; William J., a U.S. Government inspector in the Aviation Service, and Carl, a member of Troop C, Eighth U.S. Calvary. Funeral services will be held to-morrow afternoon at her home, the Rev. Tracy GRISWOLD, of the Lefferts Park Presbyterian Church, officiating. Interment at Mount Olivet Cemetery.