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In Western musical notation, a dotted note is a note with a small dot written after it. In modern practice, the first dot increases the duration of the basic note by half (the original note with an extra beam) of its original value. This means that a dotted note is equivalent to writing the basic note tied to a note of half the value – for instance, a dotted half note is equivalent to a half note tied to a quarter note. Subsequent dots add progressively halved value, as shown in the example to the right.
The use of dotted notes dates back at least to the 10th century, but the exact amount of lengthening a dot provides in early music contexts may vary. Mensural notation uses a dot of division to clarify ambiguities about its context-dependent interpretation of rhythmic values, sometimes alongside the dot of augmentation as described above. In the gregorian chant editions of Solesmes, a dot is typically interpreted as a doubling of length (see also Neume).
A pattern using longer notes alternating with shorter notes is sometimes called a dotted rhythm, whether or not it is written as such. Historical examples of music performance practices using unequal rhythms include notes inégales and swing. The precise performance of dotted rhythms can be a complex issue. Even in notation that employs dots, their performed values may be longer or shorter than the dot mathematically indicates, practices known as over-dotting or under-dotting.

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