Complex sentence: The diagrams consist of arrows and vertices with quantum numbers as labels, hence the alternative term "graphs", and the sense of the arrow is related Hermitian conjugation, which roughly corresponds to time reversal of the angular momentum states (c.f. Schrödinger equation).
Split into simpler sentences: The diagrams consist of arrows and vertices with quantum numbers as labels, hence the alternative term "graphs". The sense of each arrow is related Hermitian conjugation, which roughly corresponds to time reversal of the angular momentum states (c.f. Schrödinger equation).