Bitcoin Programming, Math symbols and meaning

Reading, writing and practising are good process for learning. But after sometime,
quite challenging to keeping up what was going on. In this writing i will try to keep
up all the variable and symbols are used in bitcoin programming.

P , is the S256Point() public key with X,y coordinate in hex format.
z , hash of the thing being signed
r , is the x coordinate of some point of R
s , is msg that signed with private key
e , is the private key

Signature(r,s) , is S256Point() of r-coordinate , s-coordinate.

A short writing for today ^^.