Hello Celia,

Odoo use polish notation to manage all filters and its operator between two filters. For that you need to have a look inside polish notation if you dont know anything about it. http://en.wikipedia.org/wiki/Polish_notation

From your question : ( (A & B) | C ) | (D & E) will be formed as like below to manage domain inside Odoo.

1) [ '|', '&', '|', '&', (A), (B), (C), (D), (E) ]

2) [ '|', '|', '&', (A), (B), (C), '&', (D), (E)  ] 

3) [ '|' , '&' , (D) , (E) , '|' , '&' , (A) , (B) , (C) ] 

I hope you will get exact idea that how domain is working in Odoo.