THEORY

There isn't any really. The notes correspond with the given chords and are based on arpeggios and chromatic lines.

If you'd like an alternate way of playing it you could try arpeggiating Em7 and Ebm7 over the A7 and Ab7, those being the m5 substitutes.

Another way is to see that A7 and Ab7 have the F# in common (the 13th of A7 and the 7th of Ab7). Emphasising that has an interesting effect: