Examples of Equivalence
The following histories are equivalent H1 = r1[x] r2[x] w1[x] c1 w2[y] c2 H2 = r2[x] r1[x] w1[x] c1 w2[y] c2 H3 = r2[x] r1[x] w2[y] c2 w1[x] c1 H4 = r2[x] w2[y] c2 r1[x] w1[x] c1
But none of them are equivalent to H5 = r1[x] w1[x] r2[x] c1 w2[y] c2because r2[x] and w1[x] conflict and r2[x] precedes w1[x] in H1 - H4, butw1[x] precedes r2[x] in H5.