This is the question that I posed myself and set out to solve before I came to MSE:
Suppose that $\{f_n\}$ is a sequence of real-valued functions defined on $[a,b]$ such that each function has the intermediate value property. Suppose there is another function $f:[a,b]\rightarrow\mathbb{R}$ such that the sequence $\{f_n\}$ approaches $f$ uniformly.
Does it follow that $f$ has the intermediate value property?
I then came to MSE and found this question and answer which is easily adapted to answer my problem in the negative---$f$ need not have the IVP.
However, before I came here I thought I came up with a proof for the opposite; that is, I thought I proved that $f$ must have the IVP. But, I cannot find the error in my reasoning. Could someone please find it?
Suppose that $x$ and $y$ are two elements of $[a,b]$ such that $f(x)<f(y)$. Let $c$ be a real number that satisfies $f(x)<c<f(y)$.
Now choose $N$ from $\mathbb{N}$ so large such that $f_n(x)<c<f_n(y)$ for every $n\geq N$.
Since every function in the sequence $\{f_n\}$ has the IVP, there is a sequence $\{c_n\}$ that begins its indexing at $N$ such that $$x<c_n<y\quad\text{and}\quad f_n(c_n)=c$$ for every $n\geq N$.
By Bolzano-Weierstrass there is a subsequence $\{c_{n_k}\}$ and an element $z$ of $[x,y]$ such that $c_{n_k}\rightarrow z$ as $k$ tends to infinity.
Clearly, the subsequence $\{f_{n_k}(c_{n_k})\}$ approaches $c$. However, the subsequence $\{f_{n_k}(c_{n_k})\}$ also approaches $f(z)$ since the convergence is uniform.
Therefore $f(z)=c$.
