In general usage, the letters in brackets indicate that the particular letter is not
(or no longer) present, but can be inferred from the context, whereas those with
the dots below may have some remnant, but are obscured in some manner.
For example: regarding the word "
'Αχελωιου" in the text you provide, the letters
χ and
ω are missing, illegible, severely damaged, etc.; whereas the letters
ε and
λ may be partially present, very worn, slightly damaged, remain in outline only, etc.
I
hope this helps.
Walter
Note:
In most cases these letters are presented in upper-case on the original
'documents', whereas in most texts they are presented in lower-case. I have
always thought this to be a little strange, and have never fully understood the
reasons behind this convention. I would have thought that it would be better
to show the text as it appears on the original. Curious!