What does this symbol mean: $ℝ^p$?

Question

in my work I have encountered this definition and I am not sure what it means:

if x is a vector of length n. what does the R superscript p mean? For context see the link and scroll to the SVC subsection: https://scikit-learn.org/stable/modules/svm.html

Answer 1

There are $n$ training vectors, indexed by $i\in\{1,...,n\}$.

The vectors are in $\mathbb R^p$, which means they each have $p$ (real number) components.

$\mathbb R^p$ is the real coordinate space of $p$ dimensions, which consists of $p$-tuples of real numbers.