The minor 7b5th arpeggio consists of the chord tones root (1), minor third (b3), diminished fifth (b5) and minor seventh (b7) which correspond to the notes A, C, Eb and G. The structure of two minor thirds (from A to C and from C to Eb) layered on top of each other plus a major third (from Eb to G) is described as half-diminished, since in contrast to the diminished seventh chord there is no consistent stacking of minor thirds.
The half-diminished arpeggio is used over minor 7b5 chords or to enrich other chords by superimposing. In the exercise, the major sixth is added to the C minor chord (C, Eb, G) by the Am7b5th arpeggio (A, C, Eb, G), which is particularly typical for the Dorian mode. The fifth degree G minor (G, B, D), on the other hand, gets superimposed by the half-diminished arpeggio with non chordal notes (A, C, E flat), which increases the urge to dissolve back to C minor.
The minor 7b5th arpeggio exercise is included in the Guitar Lovers Studies PDF or as play along track in the Jamtracks PDF which feature high graphic resolution for printing and integrated sound.