A very basic cipher

Question

The following is a relatively basic cipher I have constructed. I still hope it's entertaining.

---

_ _ _ _ _ _ _
A _ A A A
A A _
A A
A D
B
B _
A A
B H

---

The answer is the 9-letter name of a famous man who helped created this puzzle.

Small hint:

Note the mathematics tag.

Medium hint:

Look at the name of puzzle, and remember that this involves math.

Answer 1

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...