Complex sentence: He collaborated for many years with G. H. Hardy, and together they devised the first Hardy-Littlewood conjecture, a strong form of the twin prime conjecture, and the second Hardy-Littlewood conjecture.
Split into simpler sentences: He collaborated for many years with G. H. Hardy. Together they devised the first Hardy-Littlewood conjecture, a strong form of the twin prime conjecture, and the second Hardy-Littlewood conjecture.