The representation of chords, the conversion of chords, and the transformation of musical space.

1. Representation of chords: In music, chords are usually represented by arrays, and matrices in linear algebra can be used to represent chords.

2. Chord conversion: In music, chords can be converted to each other, and matrix operations in linear algebra can be used to achieve chord conversion.

3. Transformation of music space: In music, music space can be transformed, and matrices in linear algebra can be used to represent the relationship between music spaces before and after transformation.