Equality means given two grammar whether they generate the same language .
Equality checks whether two grammar are equivalent .
Inclusion means suppose you have two grammar .One grammar G1 generating some strings .
Inclusion checks whether second grammar G2 generate all the string generated by first grammar G1.
does converse holds for Equality ..what i mean is given 2 different languages can we say that these 2 different languges can be derived from the same Grammar.