The ligature is a curved line that joins two or more notes of the same sound. Its function is to add the value of these notes.
The dot is a period that is written immediately after the note it affects, and its function is to lengthen the value of the note by half more than its original value.
The double dot is two dots, one after the other, which are written immediately after the note it affects, and its function is to lengthen the note by half and a quarter more than its original value.
In popular music and jazz, the predominant meter is the 4×4 meter, called the bar meter, which follows the following writing rules: no value can start on the first beat and extend except by slur. There are 4 exceptions to this:
- The round or dotted white that attack the first time
- The white or dotted white that attack the second half
- For all other cases, ligature must be used.
Eighth notes that do not occupy the same beat cannot be barred, but 4 eighth notes that occupy the first and second beats or third and fourth beats can.