③leR+,al=al=a,VαR+，即1是零元;① VaeR+,1=R+，且a④==a==1aaa1即α的负元素是loa=a=a; VaER+;?ko(loa)= koa' =(a')* =alk =ak =(kl)oa;①(k+l)oa= a+l =a*a' = a ④a' =(k oa)④(l oa)-③ k o(a④b)= k o(ab)=(ab)* =a*bk= ak ④bk=(koa)@(kob);：R+构成实数域R上的线性空间.86.2线性空间的定义与简单性质§6.2 线性空间的定义与简单性质 ③ 1 R＋ ， a a a  = = 1 1 ,  a R＋ ，即1是零元； ④  a R＋ ， 1 a  R＋，且 1 1 a a 1 a a  = = 即 a 的负元素是 ； 1 a ⑤ 1 1 a a a = = ;  a R＋； ⑥ ( ) ( ) ( ) l l k l k kl k l a k a a a a kl a = = = = = ; ( ) ( ) ( ) k l k l k l k l a a a a a a k a l a + ⑦ + = = =  =  ⑧ ( ) ( ) ( )k k k k k k a b k ab ab a b a b  = = = =  ∴ R＋构成实数域 R上的线性空间． =  ( ) ( ) k a k b ;