[Tex/LaTex] Symbol for not conditionally independent

math-operatorsstatistics

I have previously used some code from here to produce a symbol to represent the conditionally independence of some variables. Does anyone know a method for generating a symbol for not conditionally independent. That is, the symbol below but with a forward slash through the symbol netween a and c. Thank you.

some code

\documentclass{article}

\usepackage{amsmath}
\usepackage{graphicx}

\begin{document}

% function for conditional independence - from link above    
\newcommand{\bigCI}{\mathrel{\text{\scalebox{1.07}{$\perp\mkern-10mu\perp$}}}}

a $\bigCI$ c $\mid$ b

\end{document}

which produces

Best Answer

I'm not sure about the advantage of scaling the symbol by 7%. I propose the definitions for both the scaled and unscaled symbol.

\documentclass{article}
\usepackage{amsmath,graphicx,centernot}

% function for conditional independence - from link above
\newcommand{\bigCI}{\mathrel{\text{\scalebox{1.07}{$\perp\mkern-10mu\perp$}}}}
\newcommand{\nbigCI}{\centernot{\bigCI}}

\newcommand{\CI}{\mathrel{\perp\mspace{-10mu}\perp}}
\newcommand{\nCI}{\centernot{\CI}}

\begin{document}

$a \bigCI c \mid b$ and $a \nbigCI c \mid b$

$a \CI c \mid b$ and $a \nCI c \mid b$

\end{document}

enter image description here

Related Solutions

[Tex/LaTex] Symbol for skeptical consequence

What you describe seems similar to the nonmonotonic inference relation symbol used in this paper. The main difference being that this a small space between the two characters, which I think actually looks better than having them touch.

enter image description here

\documentclass{article}
\newcommand*{\nc}[2]{#1\mathbin{\left| \sim \vphantom{#1#2} \right.}#2}%

\begin{document}
$\nc{A}{B} \qquad \nc{\frac{A}{C}}{B}$
\end{document}

Update: Here is a version where both the straight and wavy line are re-sized and the two symbols touch:

enter image description here

I have used \scalebox from the \graphicx package to resize the symbols (resize horizontally for the wavy line and vertically for the vertical bar) based on the height of the operands on either side. The \mathrlap is obtained from a TUGboat 22 article entitled a complement to \smash, \llap, and \rlap. I am not an expert in the use of the rlap type command, so perhaps some of the resize code could be simplified. I also used pgf to do the math, and this is probably overkill but I am more familiar with that then doing math in plain TeX.

\documentclass[border=2pt]{standalone}
\usepackage{amsmath}%  only needed for \dfrac
\usepackage{graphicx}% needed for \scalebox
\usepackage{pgf}%      needed for the math calculations

% http://math.arizona.edu/~aprl/publications/mathclap/
\def\mathrlap{\mathpalette\mathrlapinternal}%
\def\mathrlapinternal#1#2{\rlap{$\mathsurround=0pt#1{#2}$}}%

\makeatletter
\newdimen\@mydimen%
\newdimen\@myHeightOfBar%
\settoheight{\@myHeightOfBar}{$|$}%
\newcommand{\SetScaleFactor}[1]{%
    \settoheight{\@mydimen}{#1}%
    \pgfmathsetmacro{\scaleFactor}{\@mydimen/\@myHeightOfBar}%
}%

\newcommand*{\Scale}[2][3]{\scalebox{#1}{\ensuremath{#2}}}%

\newcommand*{\nct}[2]{%
    \SetScaleFactor{\vphantom{\ensuremath{#1#2}}}% Compute scale to be applied
    #1%
\mathrel{\Scale[\scaleFactor]{|\mathrlap{\kern-0.48ex\sim}\hphantom{\kern-0.41ex\sim}}}%
    #2%
}%

\begin{document}
$\nct{a}{b}  \qquad \nct{\frac{A}{C}}{B}  \qquad \nct{\dfrac{A}{C}}{B}$
\end{document}

An enhanced version of this solution that allows you to specify a character to be placed above and below the wavy line is available at the follow-up question: Symbol for skeptical consequence that matches the turnstile package

[Tex/LaTex] R-Integral symbol for the notes

You may try with the following code:

\documentclass{article}
\usepackage{mathtools}
\newcommand{\Rint}{\mathop{\mathrlap{\pushR}}\!\int}
\newcommand{\pushR}{\mathchoice
  {\mkern2.5mu R}
  {\scriptstyle R}
  {\scriptscriptstyle R}
  {\scriptscriptstyle R}
}
\begin{document}
\[
\left|\Rint_a^b f\right|\textstyle\left|\Rint_a^b f\right|_{\left|\Rint_a^b f\right|}
\]
\end{document}

enter image description here

The absolute value is only for demonstration purpose.

The main problem here is to adapt the R to the various formula styles, so we use \mathchoice. With \mathrlap we can build a zero width box that will not contribute to the width of the formula. Since \int is an operator, we put this zero width formula into a \mathop, then \! is used to remove the space that TeX inserts between two consecutive Operator atoms.

Next we define \pushR, that's simply a space in display style, followed by a normal size R. In text and lower styles we simply put a reduced size R. Probably the result will not be nice in \scriptscriptstyle, but it doesn't seem so important.

The same idea can be used for the principal value integral:

\newcommand{\pvint}{\mathop{\mathrlap{\pushpv}}\!\int}
\newcommand{\pushpv}{\mathchoice
  {\mkern5mu\rule[.6ex]{.5em}{1pt}}
  {\mkern2.8mu\rule[.5ex]{.35em}{.8pt}}
  {\mkern2.5mu\rule[.29ex]{.3em}{.7pt}}
  {\mkern2mu\rule[.2ex]{.2em}{.5pt}}
}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] Symbol for skeptical consequence

[Tex/LaTex] R-Integral symbol for the notes

Related Question