设有如下推理规则: R1:IF E1 AND E2 THEN A={a} (CF={0.8}) R2:IF E2 AND (E3 OR E4) THEN B={b1,b2} (CF={0.4,0.5}) R3:IF A THEN H={h1,h2,h3} (CF=(0.2,0.3,0.4}) R4:IF B THEN H={h1,h2,h3} (CF=(0.3,0.2,0.1}) 且已知初始证据的信任度分别为 F(E1)=0.5, F(E2)=0.6, F(E3)=0.7, F(E4)=0.8 若假设|D|=10,求f(H)=?