The distinctive New York guitarist Mary Halvorson makes one of her infrequent Chicago appearances tonight at the Washington Park Arts Incubator, performing in her excellent duo with violist Jessica Pavone—the set is part of the promising Chicago Jazz String Summit. As I wrote in my preview this week, that project conveys an appealingly loose rapport with a strong dose of folklike rusticity. Halvorson has been operating at an artistic peak in recent years, both leading her own dynamic bands and working as an instantly recognizable side person, and a slew of terrific recordings prove it.