Iam a physics student,I don't have any background in measuring theory.
What I know is group theory and some priliminary basics of topology.
In a book by MV Altaisky I see
I don't understand how he get expression 2.1and 2.2 and also I don't get how he connect it to famous quantum mechanical formulae 2.3. Can any one please spend some of your valuable time to help me. Thanks in advance.