A 36-year-old woman is hospitalized for treatment of a stomach ulcer has been progressively worse over several months. Radiographic studies reveals the site of involvement to be along the greater curvature, approximately 4 cm be away from the pyloric sphincter. That night the ulcer perforates, and there is considerable intra-abdominal bleeding. Surgery reveals that the ulcer has eroded through the stomach wall and has damaged the artery supplying the involved region of the stomach. Which artery was likely involved?