Our results An approximation scheme that takes an 8>0 as a parameter and finds a string s such that for each string b E B there exists a substring t of b with length L such that d(S,t)≤(1 teab and for any string g∈G d(s,g)2(1-6)d 2021/1/29 152021/1/29 15 Our Results An approximation scheme that takes an >0 as a parameter and finds a string s such that for each string b  B there exists a substring t of b with length L such that d(s, t)  (1+) db , and for any string g  G, d(s, g) (1- ) dg