Merely programming the four violin sonatas of American original Charles Ives would not have been enough for Jeremy Denk, the inquisitive and exploratory pianist, writer, and musical collaborator. That is just part of what he and beguiling, intuitive violinist Stefan Jackiw do in the simply titled program Ives Violin Sonatas. They work in reverse, starting with the boisterous Sonata No. 4, based on revival hymn tunes, and arriving, ultimately, at the joyous unpredictability of Sonata No. 1, which likewise incorporates borrowed melodies into Ives’ distinctive modernist sound. Before each sonata, Denk directs an antediluvian mixtape of sorts. Heralded vocal quartet New York Polyphony sing the songs that appear as source materials in each of the sonatas. Many of these numbers are Americana bedrock — the gospel standard Beulah Land, for instance, or the Civil War standard Tramp! Tramp! Tramp! The Boys Are Marching. In pulling out the strands of the composer’s source material, Denk humanizes Ives, whose sonatas remain as daring as they are rewarding a full century after they were written. This program offers personal context for one of America’s most original composers, thanks to one of its sharpest modern minds.