Solution (source code)

= Solution

The sequence has <uniform convergence> on $X$ if there is a function $f:X\to\mathbb R$ such that
$$
\boxed{\forall\varepsilon>0\ \exists N\ \forall n\geq N\ \forall x\in X:\quad |f_n(x)-f(x)|<\varepsilon.}
$$
The same $N$ must work for every $x$. Equivalently, the <supremum> of the error over $X$ tends to zero. In <pointwise convergence>, $N$ is allowed to depend on $x$.