Four young painters are showing recent work at the Poindexter Gallery, 46 East Fifty-seventh Street. William Scharf’s larger oils present soft, billowy shapes reflecting against a barely implied geometer’s square. His clean-washed color is reinforced with delicate line. In smaller works he seems able to concentrate his imagery more forcefully. Dan Rice paints horizontal abstractions in hazy color; Alfred Skondovitch shows moody, often stirring impressions of nocturnal landscapes; and Nora Speyer shows sketchy figure studies, disguised with exuberant but insufficiently controlled expressionist brushing.