Numeric Comparisons（数值比较）

函数 = 是数值等价谓词。它用数学意义上的值来比较数字，而忽略类型上的区别。这样，= 将把不同类型在数学意义上等价的值视为等价，而通用等价谓词 EQL 将由于其类型差异而视其不等价。（但通用等价谓词 EQUALP 使用 = 来比较数字。）如果它以超过两个参数被调用，它将只有当所有参数具有相同值时才返回真。如下所示：

The /= function, conversely, returns true only if all its arguments are different values.

The functions <, >, <=, and >= order rationals and floating-point numbers (in other words, the real numbers.) Like = and , these functions can be called with more than two arguments, in which case each argument is compared to the argument to its right.

函数 <、>、<= 和 >= 检查有理数和浮点数（也就是实数）的次序。跟 = 和 相似，这些函数也可以用超过两个参数来调用，这时每个参数都跟其右边的那个参数相比较。

要想选出几个数字中最小或最大的那个，你可以使用函数 MIN 或 MAX，其接受任意数量的实数参数并返回最小或最大值。

Some other handy functions are ZEROP, MINUSP, and PLUSP, which test whether a single real number is equal to, less than, or greater than zero. Two other predicates, EVENP and ODDP, test whether a single integer argument is even or odd. The P suffix on the names of these functions is a standard naming convention for predicate functions, functions that test some condition and return a boolean.