自定义不等于符号

Question

我怎样才能创建以下符号，或者有吗？我没有找到它？

Answer 1

\documentclass{article}
\usepackage{amsmath,graphicx}
\newcommand{\mynoteq}{\mathrel{\text{$\ooalign{$=$\cr\hidewidth$\mycross$\hidewidth\cr}$}}}
\newcommand{\mycross}{%
   \vcenter{\hbox{\scalebox{1.3}{$\times$}}}
   }

\begin{document}
  $ a \mynoteq d_{a \mynoteq d_{a \mynoteq d}}$

  $ a \mynoteq d^{a \mynoteq d^{a \mynoteq d}}$

  $ a = d$
\end{document}

Answer 2

使用图片模式：

\documentclass{article}
\usepackage{pict2e}

\makeatletter
\newcommand{\nnoteq}{\mathrel{\mathpalette\nnot@eq\relax}}
\newcommand{\nnot@eq}[2]{%
  \sbox\z@{$\m@th#1=$}%
  \vcenter{\rlap{%
    \setlength{\unitlength}{\wd0}%
    \begin{picture}(1,1)
    \linethickness{0.4pt}%
    \ifx#1\scriptstyle
      \linethickness{.9\@wholewidth}%
    \else
      \ifx#1\scriptscriptstyle
        \linethickness{.75\@wholewidth}%
      \fi
    \fi
    \roundcap
    \put(0.1,0.1){\line(1,1){0.8}}
    \put(0.1,0.9){\line(1,-1){0.8}}
    \end{picture}%
  }}%
  {=}%
}

\begin{document}

$a\nnoteq b_{\nnoteq_{\nnoteq}}$

\end{document}

Answer 3

这也许可以进一步优化：

\documentclass{article}

\usepackage{centernot,graphicx}

\newcommand{\xequal}{\mathrel{\mathchoice
  {\centernot{\reflectbox{$\neq$}}}
  {\centernot{\reflectbox{$\neq$}}}
  {\centernot{\reflectbox{$\scriptstyle\neq$}}}
  {\centernot{\reflectbox{$\scriptscriptstyle\neq$}}}}}

\begin{document}

$a = b \xequal c^{d = e \xequal f^{g = h \xequal i}}$

\end{document}