Question

已知A={a,b,c},B={-1,0,1},映射f：A-->B满足f（a）+f（b）=f（c）,写出所有满足此映射的f

Answer 1

f(a)=-1,f(b)=0,f(c)=-1

f(a)=-1,f(b)=1,f(c)=0

f(a)=0,f(b)=-1,f(c)=-1

f(a)=0,f(b)=0,f(c)=0

f(a)=0,f(b)=1,f(c)=1

f(a)=1,f(b)=-1,f(c)=0

f(a)=1,f(b)=0,f(c)=1

满足条件的映射一共有7个,列举如上.