Initial thoughts:
Nine lines in the cipher, and nine letters to find, so likely one letter per line, so we are looking for a way to turn a row of multiple symbols into a single letter.
The mathematics tag combined with the low number of distinct symbols, and the latest letter being 'H' means we could be looking at a simple A=1, B=2 etc translation, with '_' representing 0.
Which gives us:
0000000
10111
110
11
14
2
20
11
28
But that doesn't obviously translate back to letters.
More thoughts:
The rapidly reducing line lengths, and nothing above N-1 in row N makes it look like we could have numbers in different bases. So try interpreting row N in base N.
Which gives us:
0000000 (1) = 7 = G
10111 (2) = 23 = W
110 (3) = 12 = L
11 (4) = 5 = E
14 (5) = 9 = I
2 (6) = 2 = B
20 (7) = 14 = N
11 (8) = 9 = I
28 (9) = 26 = Z
So the famous man we are looking for is:
Gottfried Wilhelm von Leibniz
As for the hints:
Now that I've solved it, I realise in that the second hint pointing to this "basic" cipher, and was providing a big signpost to the different bases, which I completely failed to spot...