Consider the following schedules: S1=W2(x), W1(x), R3(x), R1(x), W2(y), R3(y), R3(z), R2(x) S2=R3(z), R3(y), W2(y), R2(z), W1(x), R3(x), W2(x), R1(x) S3=R3(z), W2(x), W2(y), R1(x), R3(x), R2(z), R3(y), W1(x) S4=R2(z), W2(x), R3(z), W1(x), W2(y), R1(x), R3(x), R3(y) (1) Which of the above schedules are local serializable? (2) Suppose the above schedule is located at an individual site. Each site has replicas of items x, y and z. Consider those schedules that are local serializable. Are they globally serializable as well?