This is a very simple question. I was wondering if anybody might know of a way to generate the symbol for the empty clause in LaTeX (small, character-sized empty square). By ``empty clause" I am referring to the propositional / first-order logic symbol which denotes a clause that is unsatisfiable by default, and is the result of a refutation from a set of unsatisfiable clauses.
2 Answers
You have several options available. Some predefined squares or a hand-made one
\newcommand{\Hsquare}{%
\text{\fboxsep=-.2pt\fbox{\rule{0pt}{1ex}\rule{1ex}{0pt}}}%
}
(requires \usepackage{amsmath}). Here's a table with some of the squares:
In the second column you find what package provides the symbol (next to \Hsquare I could have added amsmath, which is however not a font package). Note that you should say \text{\Squarepipe} if you decide for that symbol.
\usepackage{amssymb}
\newcommand{\littlesquare}{\scriptstyle{\square}}
\newcommand{\tinysquare}{\scriptscriptstyle{\square}}
usage as
square $\square$, littlesquare $\littlesquare$, and tinysquare $\tinysquare$
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Welcome to TeX.SX! Please extend your code to a minimal working example (MWE).
amssymbis needed for\square. Feb 17 at 8:46
\fbox{\phantom{x}}? or\begingroup\fboxsep1pt\fbox{\phantom{x}}\endgroupperhaps. Admittedly, this is not a square.\begingroup\fboxsep0pt\fbox{\phantom{\rule{1ex}{1ex}}}\endgroupamssymb's\square?\fboxsep=-0.5\fboxruleis possibly better. And\vrule height 1ex width 0pt \kern 1exfor filling the box is more efficient than\phantom{\rule{1ex}{1ex}}