how to represent estimated variance in LaTeX

Question

How would I represent the estimated variance symbol in LaTeX: i.e, \Var(\tau) for Var(τ) . But how to write with an inverted V symbol above the Var, basically the symbol for estimated variance

Answer 1

Something like this?

\documentclass{article}

\usepackage{amsmath}
\DeclareMathOperator{\Var}{\widehat{Var}}

\begin{document}
\[
\Var(\tau)
\]
\end{document}

Answer 2

Campa answers your question exactly. The code below shows two alternatives (both of which I prefer).

\documentclass{article}

\usepackage{amssymb}


\begin{document}
\[
 \hat V, \quad \hat{\mathbb{V}} 
\]
\end{document}