How to create a custom math mode binary operation symbol that is a combination of two binary operation symbols

math-modemath-operatorsrelation-symbolsstacking-symbolssymbols

I want to create two math mode binary operation symbols:

(1) A combination of `-` (minus symbol) and `*` (asterisk)

(2) A combination of `/` (slash symbol) and `*` (asterisk)

The desired result would be something that looks like the following but is kerned and centered properly and has the left-right spacing of a typical binary operation:

$a \minusast b = c \slashast d.$

\documentclass[12pt]{article}

\begin{document}
\Huge\[a \mathbin{-\mkern-11.5mu*} b = c \mathbin{/\mkern-8.875mu*} d.\] % my makeshift solution
\end{document}

\[a \minusast b = c \slashast d.\] % desired macro names and syntax

My question is:

How do I create the custom math mode binary relation symbols (1) and (2)?

It would also be nice if there's a version of (2) where the / symbol is adjusted to be a diagonal axis of symmetry of the * symbol.

If it's also possible, how do I generally create a custom math mode binary operation symbol that is a combination of two binary operation symbols?

Thank you.

Best Answer

Something like this? (updated to take into account the OP's additional requirement)

\documentclass{article} 

\usepackage{graphicx} % for '\rotatebox' macro
\newcommand\myslash{\rotatebox[origin=c]{-30}{$\vert$}}

\newcommand\minusast{\mathbin{\ooalign{\hss$*$\hss\cr$-$}}}
\newcommand\slashast{\mathbin{\ooalign{\hss$*$\hss\cr$\myslash$}}}

\begin{document}
$a\minusast b = c \slashast d$
\end{document}

Related Solutions

[Tex/LaTex] Relation symbol used by Conway in On Numbers and Games

Edit: Following TH's advice, this would be a better command to use:

\newcommand{\trel}{\mathrel{\mathsurround=0pt \mbox{\raisebox{1.2pt}{\tiny \textbf{\textbar }}$\rhd$}}}

(I decided to explicitly say \mathsurround=0pt rather than just calling \m@th because that way, if Mike wants to paste this into the top of his document, he won't have to call \makeatletter)

Original: I don't know what built-in symbols would correspond to the one you're describing, but if you're just trying to get something done you could use this:

\newcommand{\trel}{\mbox{\raisebox{1.2pt}{\tiny \bf \textbar }$\rhd$}}

(and then use \trel every time you want to use this relation).

It's a huge hack, but, like I said, it might be enough to get you by.

[Tex/LaTex] Defining a prefix operator with space before its argument

I didn't have the fonts so I changed the operator, but I think \mathinner does what you want here, puts some space before an ord, and doesn't stop a bin atom having bin spacing,

Top version in each of these:

enter image description here

\documentclass{article}
\usepackage{amsmath,amssymb}

\newcommand{\coerceSub}[3]{(\mathord{#1}{\smallfrown}\mathord{#2})_{#3}}

\begin{document}

In an operator application, the ``mathrel'' version looks better.
\begin{gather}
  % OK                                                                          
  \mathinner{\coerceSub uv1} x \\
  \mathrel{\coerceSub uv1} x \\
  % Not OK: no space between operator and operand                               
  \coerceSub uv1 x
\end{gather}

In an operator composition, the plain version looks better.
\begin{gather}
  \mathinner{\coerceSub uw1} \circ c \\
  % Not OK: no space between \circ and c                                        
  \mathrel{\coerceSub vw1} \circ c \\
  % OK                                                                          
  \coerceSub vw1 \circ c
\end{gather}

\end{document}

(1) A combination of - (minus symbol) and * (asterisk)

(2) A combination of / (slash symbol) and * (asterisk)