[Tex/LaTex] How to create up arrow with two heads

Question

With \twoheadrightarrow we can get arrow with two heads. Is there any command for getting two heads with up arrow?

Answer 1

One can rotate one of the existing two-headed arrows (some adjustment might be required depending on the desired position for the arrow baseline):

\documentclass{article}
\usepackage{amssymb}
\usepackage{graphicx}

\newcommand\twoheaduparrow{\mathrel{\rotatebox{90}{$\twoheadrightarrow$}}}

\begin{document}

\[
A\twoheadrightarrow B\quad A\twoheaduparrow B
\]

\end{document}

Adding [origin=<origin>] as an option to \rotate, the center for rotation can be changed (possible values for <origin> are t (top),b (bottom),l (left),r (right),c (center), and B (baseline)):

\documentclass{article}
\usepackage{amssymb}
\usepackage{graphicx}

\newcommand\twoheaduparrow{\mathrel{\rotatebox[origin=c]{90}{$\twoheadrightarrow$}}}

\begin{document}

\[
A\twoheadrightarrow B\quad A\twoheaduparrow B
\]

\end{document}

In a comment it has been requested a definition without using additional packages; in this case, with a little more work, one can build the symbol using \ooalign and two shifted \uparrows:

\documentclass{article}

\makeatletter
\newcommand\twoheaduparrow{%
\mathrel{\mathchoice
  {\raise2pt\hbox{%
  \ooalign{\hss$\uparrow$\hss\cr\lower2pt\hbox{%
  $\uparrow$}}}}
  {\raise2pt\hbox{%
  \ooalign{\hss$\uparrow$\hss\cr\lower2pt\hbox{%
  $\uparrow$}}}}
  {\raise1.5pt\hbox{%
  \ooalign{\hss$\scriptstyle\uparrow$\hss\cr\lower1.5pt\hbox{%
  $\scriptstyle\uparrow$}}}}
  {\raise1.1pt\hbox{%
  \ooalign{\hss$\scriptscriptstyle\uparrow$\hss\cr\lower1.1pt\hbox{%
  $\scriptscriptstyle\uparrow$}}}}
}}

\begin{document}

\[
A\twoheaduparrow B\quad {\textstyle A\twoheaduparrow B}\quad A_{A\twoheaduparrow B}\quad L_{A_{A\twoheaduparrow B}}
\]

\[
A\uparrow B\quad {\textstyle A\uparrow B}\quad A_{A\uparrow B}\quad L_{A_{A\uparrow B}}
\]

\end{document}