在定义了正分数后可以定义有正分数参加的数的加法和乘法，并可以验证运算律。

After defined positive fraction Numbers, we might define addition and multiplication for positive fraction Numbers, and then we can also verify operation laws.

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这里我们用到了乘法结合律也可以用消去律，本来这些运算律是对正整数乘法适用的，但对于有分数参加的乘法我们也规定适用。

Here we have used the associative law or the cancellation law for multiplication, which are satisfied for natural Numbers, now we assume they are satisfied with fraction Numbers.

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使用符号运算方法设计了系统闭环控制律和大攻角下的过失速控制律。

The control laws of the inner closed loop system and post stall maneuver are obtained through using symbol operations design.

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