## Discrete Mathematics with Applications 4th Edition

a. "the set of all positive real numbers $x$ such that zero is less than $x$ and $x$ is less than one" b. "the set of all real numbers $x$ such that $x$ is less than or equal to zero, or $x$ is greater than or equal to one" c. "the set of all integers $n$ such that $n$ is a factor of 6" d. "the set of all positive integers $n$ such that $n$ is a factor of 6"
It is important to know the names of the sets $Z$ (the integers), $Q$ (the rationals), and $R$ (the reals). A superscript plus sign (e.g., $Z^{+}$) denotes the positive elements of the set. It is also important to remember that the vertical bar | is read "such that."