判定问题的形式化表达 Definition 2.3.2.1.A decision problem is a triple (L,U,S)where is an alphabet and L CUC*.An algorithm A solves (decides)the decision problem (L,U,>if,for every x EU, ()A(x)=1fx∈L,amd Pay attention to )A(x)=0fx∈U-L(x年L. the word "decide" For many decision problems (L,U,>we assume U =*In that case we shall use the short notation (L,instead of (L,*S).判定问题的形式化表达 Pay attention to the word “decide