Hi:
Reading a book on ring theory, I find the symbol aRb, where R is a ring and a, b are elements of R. Can somebody give me a definition of aRb? I'd be very grateful if somebody sends one. Thanks for reading.

Hi:
Reading a book on ring theory, I find the symbol aRb, where R is a ring and a, b are elements of R. Can somebody give me a definition of aRb? I'd be very grateful if somebody sends one. Thanks for reading.