eix supports logical operators (-a, -o). Even though the man page talks about "--not", the other two are only mentioned at the definition of expressions. they also have long forms "--and", "--or". There should be mentions of the logical operators within the man page text. A small patch will follow. Reproducible: Always
Created attachment 158531 [details, diff] mentions AND, OR within the man page text
Thanks. Some further notes concerning expressions and there logic were necessary anyway. Fixed in eix svn trunk (>=eix-0.13.2).
Closing since eix-0.13.2 is now in the tree