# Directory `macros/latex/contrib/frege`

frege.sty - a LaTeX2e package for typesetting begriffsschrift This package is based on begriff.sty released under the GNU General Public License. Copyright (C) 2003 by Josh Parsons Since version 1.3 this package also makes use of the bguq package by J.J. Green. Changes with respect to begriff.sty correct relative lengths of the content stroke with respect to other strokes attached to it; content strokes point at the middle of the following symbols, rather than the bottom; greater width for the assertion stroke as compared to the content stroke; a more intuitive structure for the conditional (arguments are now given in the same order as they appear on the left of a completed formula); the command for the conditional with empty arguments now results in a vertical line (conditional stroke) on it's own the other strokes are added as the arguments; the linewidth is properly accounted for so that things remain properly centered when scaled; frege.sty defines the following basic commands: \Fcontent[1] - plain content stroke \Fncontent[1] - negated content stroke \Fnncontent[1] - twice negated content stroke \Faconten[1] - asserted content stroke \Fancontent[1] - asserted negated content stroke \Fanncontent[1] - asserted twice negated content stroke \Fquant[1]{a} - content stroke with quantifier \Fnquant[1]{a} - negated quantifier \Fnnquant[1]{a} - twice negated quantifier \Fquantn[1]{a} - quantifier with negated content \Fquantnn[1]{a} - quantifier with twice negated content \Fnquantn[1]{a} - negated quantifier with negated content \Fnquantnn[1]{a} - negated quantifier with twice negated content \Fnnquantn[1]{a} - twice negated quantifier with negated content \Fnnquantnn[1]{a} - twice negated quantifier with twice negated content \Faquant[1]{a} - asserted content stroke with quantifier \Fanquant[1]{a} - asserted negated quantifier \Fannquant[1]{a} - asserted twice negated quantifier \Faquantn[1]{a} - asserted quantifier with negated content \Faquantnn[1]{a} - asserted quantifier with twice negated content \Fanquantn[1]{a} - asserted negated quantifier with negated content \Fanquantnn[1]{a} - asserted negated quantifier with twice negated content \Fannquantn[1]{a} - asserted twice negated quantifier with negated content \Fannquantnn[1]{a} - asserted twice negated quantifier with twice negated content while this may look like a daunting list think of it as just two commands: \Fcontent[1] - generates a content stroke \Fquant[1]{a} - generates a quantifier with variable a Adding an "a" after the "\F" adds an assertion stroke to the front of the command, this may be followed by one two or no "n" to add one two or no negations to the stroke. Next comes the name of the command either "content" or "quant". "quant" may then be followed by another one two or no "n" which will add one two or no negations after the quantifier to it's content stroke. All commands may be used in either text or math mode. All the above commands produce output of the same length and may be arbitrarly combined to produce longer composite formulas. Since version 1.1 each of the basic strokes also has an optional argument with default value one, that scales the total length of the stroke (\Fbaselength), so that an optional argument of [.5] will produce a stroke half as long. Warning: setting a length shorter than what is needed to fit all the options of a stroke leads to negative lengths and hence unpredictable results. Since version 1.3 it is also possible to call all the above commands without the word "content" for the content strokes and with just "q" instead of the word "quant" for the quantifiers. frege.sty defines the following more complex commands: \Fconditional[<option>]{<consequent>}{<antecedent>} \Fbox{<begriffsschrift formula with at least one conditional>} \Fbracket{<begriffsschrift formula with at least one conditional>} \Fargument[<premise 0>]{<premise 1>}{<premise 2>}{<conclusion>} \Fstrut[1] The final two have been added in version 1.2. The following shorthands for the above commands have been introduced in version 1.3: \Fcdt, \Fb, \Fbb, \Farg, \Fs; The "Fconditional" command requires a mixture of the commands defined by frege.sty and normal mathmode input to produce begriffsschrift. A implies B would be written like this: \Fconditional[\Facontent]{\Fcontent B}{\Fcontent A} This produces the two dimensional fregean conditional symbol with B lined up above A. In addition the "Fconditional" command may be arbitrarily nested to produce any begriffsschrift formula possible. All begriffsschrift symbol can be made without the use of the optional argument, it exists only for convenience. "Fbracket" is just the same as "\left(\Fbox\right)" everything said about "Fbox" applies equally to "Fbracket". A completed formula of begriffsschrift that includes at least one conditional, should always be placed in an "Fbox" this ensures it is given enough space in the output behaves correctly with respect to the text around it and works correctly within environments such as align*. "Fargument" arranges two begriffsschrift formulas above each other and seperates them from a third by a horizontal line. The option is for the name of a premise written elsewhere and will outout (name): to the left of the horizontal line. "Fstrut" is like a invisible content stroke. Like all other basic strokes, it may be scaled using it's optional argument. Fstrut is to be used in conjunction with Fargument to ensure the formulas line up properly. The final result may also be modified by changing the following lengths using the \setlength{<lengthname>}{<value>} command. The lengths and there default values are given as follows: length: default value: description: \Fbaselength 20pt the length of a single basic stroke \Flinewidth 0.5pt the width of all lines other than the assert stroke \Fspace 2pt seperation between begriffsschrift and text/formula \Fassertwidth 3\Flinewidth the width of the assert stroke \Fraiseheight 1ex-\Flinewidth the height of content strokes above the baseline \Fnegsep 3\Flinewidth the sepparation between a double negation \Fnegshort 2\Flinewidth the space between negation stroke and baseline \Fquantwidth 6pt width of the semi circular quantifier depression Since version 1.3 it is possible to load this package using the "bguq" option: \usepackage[bguq]{frege} if the bguq option is enabled all quantifiers will use the bguq character provided by the bguq package by J.J. Green rather than the qbezier used by this package. This means the bguq package must be installed to use the option. (It can be found on ctan: http://www.ctan.org/pkg/bguq). Warning: as it stands the bguq character scales with font while the rest of the symbols provided by this package do not. Also, the bguq character will not respond to a change in Flinewidth. For more examples and info see accompanying manual (frege.pdf or frege.tex) Everything released under GNU General Public License.

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## frege – Typeset fregean Begriffsschrift

The package defines a number of new commands for typesetting fregean Begriffsschrift in LaTeX.

It is loosely based on the package begriff, and offers a number of improvements including better relative lengths of the content stroke with respect to other strokes, content strokes that point at the middle of lines rather than the bottom, a greater width for the assertion stroke as compared to the content stroke, a more intuitive structure for the conditional, greater care taken to allow for the linewidth in the spacing of formulas.

Package | frege |

Version | 1.3 |

Licenses | GNU General Public License |

Maintainer | Quirin Pamp |

Contained in | TeX Live as frege MiKTeX as frege |

Topics | Logic Maths |

See also | grundgesetze bguq begriff |