The term 'arc-shaped musical notation' refers to a type of musical notation known as a SLUR. A SLUR is a curved line that connects two or more notes of the same pitch, indicating that they should be played in a smooth, connected manner. Slurs are used to indicate legato playing, which is a style of playing where notes are connected together without any breaks or pauses. Slurs can also be used to indicate a change in articulation, such as from staccato to legato.