Complex sentence: It provides an alternative to Roman-numeral analysis or diatonic function theory, both of which interpret harmonies in relation to specific tonics, and is particularly useful when determination of a tonic for a given triadic passage feels forced or arbitrary.
Split into simpler sentences: It provides an alternative to Roman_numeral_analysis and diatonic function theory, both of which interpret harmonies in relation to specific tonics. It is particularly useful when determination of a tonic for a given triadic passage feels forced or arbitrary.