Given
$ R_1 = \{(1,2),(5,3)\}\quad\quad R_2 = \{(6,4),(5,7)\}$
What is $R_2 \circ R_1$?
Because in my understanding, using the example
$ R_3 = \{(1,2),(3,4)\} \quad\quad R_4 = \{ (2,5),(6,7)\}$
Then $R_4\circ R_3 = \{(1,5)\}.\;$ Am I correct?
So given that case, if $R_2 \circ R_1 = (a,b),\;a$ comes from $R_1$, right? While $b$ comes from $R_2$?