*Pre-emptive embarassment for missing a previous identical suggestion*
Well, I was wondering if as there are 26 letters in the english language, and the letter uses 5 letters up to 5 times in a row, each letter and number of letters maps onto an english letter: θ being a, for exmaple, omega b, lambda c, delta d and phi e to start with, then θθ being f, θθθ k, etc, getting something like this for the first line:
AGCNAGDUCDBEDBCBFHIAHEDCEFGECEDHEACDEFFEBCIFDCOBNCEDAEIBAEBDCEDBAIAHEC
The most likely possibility, and the analysis so far seems to support this, is that the singles are the 5 most frequent, then the doubles the 6th to 10th in frequency, etc etc. And there is no z or something, I don't like the last letter, and have no idea about spaces. Those might be hurdles to cross later. Anyway, all that needs to happen, as it is simple to do the initial greek-to-english-cipher on this message, is to exchange the singles with e-t-a-o-i in all possible combinations, then the doubles i-n-s-h-r in all combinations. Alternatively, one could simply transliterate the whole message into ciphered english, then use analysis.
While it seems basic for someone who names themselves after a description of a mathematical function, so far, analysis DOES put the singles as the most common 5 letters in the first line, and has a nearly perfectly complete second line as well. Let me know what you think, or if I explained unclearly.