Specific calligraphic font for lowercase g

Question

I am looking for a command to obtain the following calligraphic lowercase g in math mode:

I have been looking around but to no avail for now.

Answer 1

It is an alternative glyph for capital Script G, provided by the professional (paid) MathTime Professional II fonts. If you have the complete set of fonts installed, you can get that symbol using \altG.

Btw, if you are looking for free alternatives, you can look at the newtxmath package as suggested by Sebastiano or the mathalpha package.

Answer 2

For reference, if you use unicode maths fonts, unicode-aware engines like xetex or lualatex, then unicode-math package provides access to 𝒢 U+1D4A2 and 𝓖 U+1D4D6 with \mscrG and\mbfscrG. Direct input can also be used.

Random sample from a TL install on Android under Termux. Blank = either a Windows font, or a user font not installed, or glyph not present

\documentclass[12pt,varwidth,border=6pt]{standalone}
\usepackage{xcolor}
\pagecolor{red!3}
\usepackage{unicode-math}
\setmathfont{XITS Math}[Colour=blue]
\setmathfontface\masana{Asana Math}
\setmathfontface\mdejavu{notoserif}%{DejaVu Math}
\setmathfontface\mtgdeja{notoserif}%{TeX Gyre DejaVu Math}
\setmathfontface\mpagella{TeX Gyre Pagella Math}
\setmathfontface\mbonum{TeX Gyre Bonum Math}
\setmathfontface\mschola{TeX Gyre Schola Math}
\setmathfontface\mtermes{TeX Gyre Termes Math}
\setmathfontface\mlatin{Latin Modern Math}
\setmathfontface\mcambria{notoserif}%{Cambria Math}
\setmathfontface\mfira{Fira Math}
\setmathfontface\mfreeserif{FreeSerif}
\setmathfontface\mlibert{Libertinus Math}
\setmathfontface\mnoto{notoserif}%{Noto Sans Symbols}
\setmathfontface\mqui{notoserif}%{Quivira}
\setmathfontface\mstixtwo{STIX Two Math}
\setmathfontface\mstixgen{notoserif}%{STIXGeneral}
\setmathfontface\msymbola{notoserif}%{Symbola}
\setmathfontface\mgaramond{\detokenize{Garamond-Math}}
\newcommand\mfsize{\Huge}
\setmainfont{Noto Serif}


\newcommand\themassym{𝒢}%,

\begin{document}
\section*{Sampling {\mfsize $\themassym $}}

\textbackslash mscrG = $\mscrG$,
\textbackslash mbfscrG = $\mbfscrG$.

\vspace{24pt}

\begin{tabular}{rccl}
XITS Math & \mfsize $\themassym$
& \mfsize $\mcambria \themassym$ & Cambria Math \\
\ &\ & \ & \ \\
Asana Math & \mfsize $\masana {\themassym}$
& \mfsize $\mfira \themassym$ & Fira Math \\
\ &\ & \ & \ \\
DejaVu Math & \mfsize $\mdejavu \themassym$
& \mfsize $\mfreeserif \themassym$ & FreeSerif \\
\ &\ & \ & \ \\
Tex Gyre Bonum Math & \mfsize $\mbonum \themassym$
& \mfsize $\mlibert \themassym$ & Libertinus Math \\
\ &\ & \ & \ \\
Tex Gyre DejaVu Math & \mfsize $\mtgdeja \themassym$
& \mfsize $\mnoto \themassym$ & Noto Sans Symbols \\
\ &\ & \ & \ \\
Tex Gyre Pagella Math & \mfsize $\mpagella \themassym$
& \mfsize $\mqui \themassym$ & Quivira \\
\ &\ & \ & \ \\
Tex Gyre Schola Math & \mfsize $\mschola \themassym$
& \mfsize $\mstixtwo \themassym$ &STIX Two Math \\
\ &\ & \ & \ \\
Tex Gyre Termes Math & \mfsize $\mtermes \themassym$
& \mfsize $\mgaramond \themassym$ & Garamond-Math \\
\ &\ & \ & \ \\
Latin Modern Math & \mfsize $\mlatin \themassym$
& \mfsize $\msymbola \themassym$ & Symbola \\
\end{tabular}

\end{document}

Answer 3

You could use free text/math fonts like newtxtext, newtxmath. I have added another option \rsfscr{G} that work under \DeclareMathAlphabet\rsfscr{U}{rsfso}{m}{n}.

\documentclass[a4paper,12pt]{article}
\usepackage{newtxtext,newtxmath}
\usepackage{mathrsfs}
\DeclareMathAlphabet{\mathbb}{U}{msb}{m}{n}
\DeclareMathAlphabet\rsfscr{U}{rsfso}{m}{n}
\begin{document}
\[P_t(t<\tau<t+\Delta)=\mathbb{E}[\mathbb{I}_{\,t<\tau<t+\Delta}]\mathscr{G},\rsfscr{G}]\] 
\end{document}