Complex sentence: Incidentally, "tatpurusha" is a tatpurusha ("this man "--meaning someone's agent), while"caturtitatpurusha" is a karmadhariya, being both dative, and a tatpurusha.
Split into simpler sentences: Incidentally, "tatpurusha" is a tatpurusha ("this man "--meaning someone's agent). The term"caturti-tatpurusha" is itself a karmadhariya (a subtype of tatpurusha), being both dative, and a tatpurusha.