Veronica Jochum's recital at the Terrace Theater Saturday afternoon suffered a case of the splits. In the first half the pianist showed herself to be an able and cultivated artist of considerable insight, with a warm and informative stage manner. In the second half, her playing verged on sloppiness and that, plus a memory lapse, broke the bond with her audience.

Jochum opened with a B-minor Haydn sonata, underlining its expressiveness with carefully placed stresses and hesitations. Her romantic approach echoed that of one of her former teachers, Rudolf Serkin.

After a spacious reading of some Brahms pieces, Jochum launched with enthusiasm into a discussion of Donald Harris' 1981 "Balladen," which is dedicated to her and her husband. It was helpful to know, as Jochum pointed out, that Harris used fragments from Brahms and Chopin ballades in this "meditation," as he calls it. But it was equally important to forget this once the music started, lest musical detective work dominate one's thinking. The broad flow of Harris' thought was projected with intelligent affection by Jochum. The composer was on hand to acknowledge the audience's applause.

After intermission Jochum played Beethoven's Sonata Op. 81, "Les Adieux," as if it were an old friend she had not seen for a while. Forgotten notes plus her lack of focus and clarity evoked a disappointment that her adept handling of Bartok's "Improvisations" could not dispel