What is This Math Font Called?

Question

I would like to know what is this font called? How can I reproduce it? I know that it is neither \mathsf{} nor \mathcal{}.

Is there any reference where can I find all mathematical fonts?

Answer 1

Something too close?

The main difficulty is with the "not \mathcal{D}" character. But, we can go too close using the Zapf Chancery characters. For these, we declare the math font:

\DeclareMathAlphabet{\mathpzc}{OT1}{pzc}{m}{it}      

The rest of the equation can be typeset with mathptmx.

\documentclass{article}
\usepackage{mathptmx}
\usepackage{amsmath}
\DeclareMathAlphabet{\mathpzc}{OT1}{pzc}{m}{it}
\begin{document}

\begin{equation}
\begin{aligned}
\max_{\mathbf{x}} \quad  & \sum_{i\in \mathpzc{D}}w_i \sum_{k = 1}^{K} R_{ik}^{(D)}(\mathbf{x}) \\
  \text{s. t.}\quad & \sum_{i\in \mathpzc{D}}x_{ik}P_{D_i}g_{ii}(k)\le Q_k, \quad\forall k, \\
                    & x_{ik}\in [0,1],
\end{aligned}
\end{equation}

\end{document}

Answer 2

TeX Gyre Termes. There is a difference for the∀` symbol :

\documentclass{article}
\usepackage{newtxmath, newtxtext}

\begin{document}

\begin{align*}
  \max_{\mathbf{x}} & \sum_{i\in \mathcal{D}}w_i \sum_{k = 1}^{K} R_{ik}^{(D)}(\mathbf{x}) \\
  \text{s. t.}\quad & \sum_{i\in \mathcal{D}}x_{ik}P_{D_i}g_{ii}(k)\le Q_k, \quad\forall k, \\
                    & x_{ik}\in [0,1]
\end{align*}

\end{document}