What do these Roman Numerals mean?

[mastersrhythm]

Just purchased John Patitucci's 60 Melodic Etudes. There are Roman Numerals UNDER the line. Wondering if anyone can shed some light on their meaning. Is this left hand fretboard position or something?

[Mayers]

the string you should use to play that section. and from what I see, it is a book written for DB player first because you also have the DB fingering.

[noahw1]

The fingerings look like electric bass fingerings to me as that's how I might finger that line although I would probably use the 4th finger to hit the G and A instead of the 2nd. Something to try I guess.
The roman numerals are like Mayers said the corresponding string. B=5, E=4, A=3, D=2, G=1.

[mastersrhythm]

OMG...I didn't even thing of that. Duh! Thanks for that guys. Makes perfect sense. Tie that with the fingering and you have the proper shifts as well.

[mastersrhythm]

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[onlyclave]

Those are string numbers. Start that scale on the A string (III).

G = I
D = II
A = III
E = IV