Definitions

Term Notation Example(s) We say in English …
sequence \(x_1, \ldots, x_n\) A sequence \(x_1\) to \(x_n\)
summation \(\sum_{i=1}^n x_i\) or \(\displaystyle{\sum_{i=1}^n x_i}\) The sum of the terms of the sequence \(x_1\) to \(x_n\)
all reals \(\mathbb{R}\) The (set of all) real numbers (numbers on the number line)
all integers \(\mathbb{Z}\) The (set of all) integers (whole numbers including negatives, zero, and positives)
all positive integers \(\mathbb{Z}^+\) The (set of all) strictly positive integers
all natural numbers \(\mathbb{N}\) The (set of all) natural numbers. Note: we use the convention that \(0\) is a natural number.
piecewise rule definition \(f(x) = \begin{cases} x & \text{if~}x \geq 0 \\ -x & \text{if~}x<0\end{cases}\) Define \(f\) of \(x\) to be \(x\) when \(x\) is nonnegative and to be \(-x\) when \(x\) is negative
function application \(f(7)\) \(f\) of \(7\) or \(f\) applied to \(7\) or the image of \(7\) under \(f\)
\(f(z)\) \(f\) of \(z\) or \(f\) applied to \(z\) or the image of \(z\) under \(f\)
\(f(g(z))\) \(f\) of \(g\) of \(z\) or \(f\) applied to the result of \(g\) applied to \(z\)
absolute value \(\lvert -3 \rvert\) The absolute value of \(-3\)
square root \(\sqrt{9}\) The non-negative square root of \(9\)

Definitions

Term Notation Example(s) We say in English …
sequence \(x_1, \ldots, x_n\) A sequence \(x_1\) to \(x_n\)
summation \(\sum_{i=1}^n x_i\) or \(\displaystyle{\sum_{i=1}^n x_i}\) The sum of the terms of the sequence \(x_1\) to \(x_n\)
all reals \(\mathbb{R}\) The (set of all) real numbers (numbers on the number line)
all integers \(\mathbb{Z}\) The (set of all) integers (whole numbers including negatives, zero, and positives)
all positive integers \(\mathbb{Z}^+\) The (set of all) strictly positive integers
all natural numbers \(\mathbb{N}\) The (set of all) natural numbers. Note: we use the convention that \(0\) is a natural number.
piecewise rule definition \(f(x) = \begin{cases} x & \text{if~}x \geq 0 \\ -x & \text{if~}x<0\end{cases}\) Define \(f\) of \(x\) to be \(x\) when \(x\) is nonnegative and to be \(-x\) when \(x\) is negative
function application \(f(7)\) \(f\) of \(7\) or \(f\) applied to \(7\) or the image of \(7\) under \(f\)
\(f(z)\) \(f\) of \(z\) or \(f\) applied to \(z\) or the image of \(z\) under \(f\)
\(f(g(z))\) \(f\) of \(g\) of \(z\) or \(f\) applied to the result of \(g\) applied to \(z\)
absolute value \(\lvert -3 \rvert\) The absolute value of \(-3\)
square root \(\sqrt{9}\) The non-negative square root of \(9\)