Consider two transactions T$1$ and T$2,$ which pair$($s$)$ of operations is in conflict?

T$1$ Read$($X$),$ T$2$ Write$($Y$)$

T$1$ Write$($Y$),$ T$2$ Write$($Y$)$

T$1$ Read$($X$),$ T$2$ Read$($X$)$

T$1$ Write$($Z$),$ T$2$ Read$($Z$)$