Range based Method Definition 4(Pivotal Quadruple a quadruple <LLul, d, j)is a pivotal quadruple, if it satisfies (1) L, u is a sub-range of a d-th level nodes range (2 )for any string S with Id in [, u] ED(S[l,d+1],q[1,j+1])>ED(S[1,d2q[1,j) B3)strings with IDI-l or u+ I do not satisfy conditions(1)or(2) 2/2/2021 Topk Search(@ ICD E2013 41142Range based Method  Definition 4 (Pivotal Quadruple): A quadruple ⟨[l, u], d, j⟩ is a pivotal quadruple, if it satisfies (1) ⟨l, u⟩ is a sub-range of a d-th level node’s range; (2) for any string s with ID in [l, u], ED(s[1, d + 1], q[1, j + 1]) > ED(s[1, d], q[1, j]); (3) strings with ID l − 1 or u + 1 do not satisfy conditions (1) or (2). 2/2/2021 TopkSearch @ ICDE2013 41/42