Harmonic minor keys are used when writing chords ... the triads in C major are as follows: Triads can be indicated by Roman numerals of the degrees of the scale. In the jazz styles of Gershwin ...

The CAGED chord ... C major arpeggios here, reflecting the changing chords in the backing. If you look closely at these arpeggio/chord shapes and compare them to shape 3 of the major pentatonic ...