Complex sentence: If faces are all regular, the hexagonal prism is a semiregular polyhedron, more generally, a uniform polyhedron, and the fourth in an infinite set of prisms formed by square sides and two regular polygon caps.
Split into simpler sentences: If faces are all regular, the hexagonal prism is a semiregular polyhedron. This is the fourth in an infinite set of prisms formed by square sides and two regular polygon caps.