\documentclass[12pt,titlepage]{article} \usepackage{amsmath} \usepackage{mathrsfs} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsthm} \usepackage{mathtools} \usepackage{graphicx} \usepackage{color} \usepackage{ucs} \usepackage[utf8x]{inputenc} \usepackage{xparse} \usepackage{hyperref} %----Macros---------- % % Unresolved issues: % % \righttoleftarrow % \lefttorightarrow % % \color{} with HTML colorspec % \bgcolor % \array with options (without options, it's equivalent to the matrix environment) % Of the standard HTML named colors, white, black, red, green, blue and yellow % are predefined in the color package. Here are the rest. \definecolor{aqua}{rgb}{0, 1.0, 1.0} \definecolor{fuschia}{rgb}{1.0, 0, 1.0} \definecolor{gray}{rgb}{0.502, 0.502, 0.502} \definecolor{lime}{rgb}{0, 1.0, 0} \definecolor{maroon}{rgb}{0.502, 0, 0} \definecolor{navy}{rgb}{0, 0, 0.502} \definecolor{olive}{rgb}{0.502, 0.502, 0} \definecolor{purple}{rgb}{0.502, 0, 0.502} \definecolor{silver}{rgb}{0.753, 0.753, 0.753} \definecolor{teal}{rgb}{0, 0.502, 0.502} % Because of conflicts, \space and \mathop are converted to % \itexspace and \operatorname during preprocessing. % itex: \space{ht}{dp}{wd} % % Height and baseline depth measurements are in units of tenths of an ex while % the width is measured in tenths of an em. \makeatletter \newdimen\itex@wd% \newdimen\itex@dp% \newdimen\itex@thd% \def\itexspace#1#2#3{\itex@wd=#3em% \itex@wd=0.1\itex@wd% \itex@dp=#2ex% \itex@dp=0.1\itex@dp% \itex@thd=#1ex% \itex@thd=0.1\itex@thd% \advance\itex@thd\the\itex@dp% \makebox[\the\itex@wd]{\rule[-\the\itex@dp]{0cm}{\the\itex@thd}}} \makeatother % \tensor and \multiscript \makeatletter \newif\if@sup \newtoks\@sups \def\append@sup#1{\edef\act{\noexpand\@sups={\the\@sups #1}}\act}% \def\reset@sup{\@supfalse\@sups={}}% \def\mk@scripts#1#2{\if #2/ \if@sup ^{\the\@sups}\fi \else% \ifx #1_ \if@sup ^{\the\@sups}\reset@sup \fi {}_{#2}% \else \append@sup#2 \@suptrue \fi% \expandafter\mk@scripts\fi} \def\tensor#1#2{\reset@sup#1\mk@scripts#2_/} \def\multiscripts#1#2#3{\reset@sup{}\mk@scripts#1_/#2% \reset@sup\mk@scripts#3_/} \makeatother % \slash \makeatletter \newbox\slashbox \setbox\slashbox=\hbox{$/$} \def\itex@pslash#1{\setbox\@tempboxa=\hbox{$#1$} \@tempdima=0.5\wd\slashbox \advance\@tempdima 0.5\wd\@tempboxa \copy\slashbox \kern-\@tempdima \box\@tempboxa} \def\slash{\protect\itex@pslash} \makeatother % math-mode versions of \rlap, etc % from Alexander Perlis, "A complement to \smash, \llap, and lap" % http://math.arizona.edu/~aprl/publications/mathclap/ \def\clap#1{\hbox to 0pt{\hss#1\hss}} \def\mathllap{\mathpalette\mathllapinternal} \def\mathrlap{\mathpalette\mathrlapinternal} \def\mathclap{\mathpalette\mathclapinternal} \def\mathllapinternal#1#2{\llap{$\mathsurround=0pt#1{#2}$}} \def\mathrlapinternal#1#2{\rlap{$\mathsurround=0pt#1{#2}$}} \def\mathclapinternal#1#2{\clap{$\mathsurround=0pt#1{#2}$}} % Renames \sqrt as \oldsqrt and redefine root to result in \sqrt[#1]{#2} \let\oldroot\root \def\root#1#2{\oldroot #1 \of{#2}} \renewcommand{\sqrt}[2][]{\oldroot #1 \of{#2}} % Manually declare the txfonts symbolsC font \DeclareSymbolFont{symbolsC}{U}{txsyc}{m}{n} \SetSymbolFont{symbolsC}{bold}{U}{txsyc}{bx}{n} \DeclareFontSubstitution{U}{txsyc}{m}{n} % Manually declare the stmaryrd font \DeclareSymbolFont{stmry}{U}{stmry}{m}{n} \SetSymbolFont{stmry}{bold}{U}{stmry}{b}{n} % Manually declare the MnSymbolE font \DeclareFontFamily{OMX}{MnSymbolE}{} \DeclareSymbolFont{mnomx}{OMX}{MnSymbolE}{m}{n} \SetSymbolFont{mnomx}{bold}{OMX}{MnSymbolE}{b}{n} \DeclareFontShape{OMX}{MnSymbolE}{m}{n}{ <-6> MnSymbolE5 <6-7> MnSymbolE6 <7-8> MnSymbolE7 <8-9> MnSymbolE8 <9-10> MnSymbolE9 <10-12> MnSymbolE10 <12-> MnSymbolE12}{} % Declare specific arrows from txfonts without loading the full package \makeatletter \def\re@DeclareMathSymbol#1#2#3#4{% \let#1=\undefined \DeclareMathSymbol{#1}{#2}{#3}{#4}} \re@DeclareMathSymbol{\neArrow}{\mathrel}{symbolsC}{116} \re@DeclareMathSymbol{\neArr}{\mathrel}{symbolsC}{116} \re@DeclareMathSymbol{\seArrow}{\mathrel}{symbolsC}{117} \re@DeclareMathSymbol{\seArr}{\mathrel}{symbolsC}{117} \re@DeclareMathSymbol{\nwArrow}{\mathrel}{symbolsC}{118} \re@DeclareMathSymbol{\nwArr}{\mathrel}{symbolsC}{118} \re@DeclareMathSymbol{\swArrow}{\mathrel}{symbolsC}{119} \re@DeclareMathSymbol{\swArr}{\mathrel}{symbolsC}{119} \re@DeclareMathSymbol{\nequiv}{\mathrel}{symbolsC}{46} \re@DeclareMathSymbol{\Perp}{\mathrel}{symbolsC}{121} \re@DeclareMathSymbol{\Vbar}{\mathrel}{symbolsC}{121} \re@DeclareMathSymbol{\sslash}{\mathrel}{stmry}{12} \re@DeclareMathSymbol{\bigsqcap}{\mathop}{stmry}{"64} \re@DeclareMathSymbol{\biginterleave}{\mathop}{stmry}{"6} \re@DeclareMathSymbol{\invamp}{\mathrel}{symbolsC}{77} \re@DeclareMathSymbol{\parr}{\mathrel}{symbolsC}{77} \makeatother % \llangle, \rrangle, \lmoustache and \rmoustache from MnSymbolE \makeatletter \def\Decl@Mn@Delim#1#2#3#4{% \if\relax\noexpand#1% \let#1\undefined \fi \DeclareMathDelimiter{#1}{#2}{#3}{#4}{#3}{#4}} \def\Decl@Mn@Open#1#2#3{\Decl@Mn@Delim{#1}{\mathopen}{#2}{#3}} \def\Decl@Mn@Close#1#2#3{\Decl@Mn@Delim{#1}{\mathclose}{#2}{#3}} \Decl@Mn@Open{\llangle}{mnomx}{'164} \Decl@Mn@Close{\rrangle}{mnomx}{'171} \Decl@Mn@Open{\lmoustache}{mnomx}{'245} \Decl@Mn@Close{\rmoustache}{mnomx}{'244} \makeatother % Widecheck \makeatletter \DeclareRobustCommand\widecheck[1]{{\mathpalette\@widecheck{#1}}} \def\@widecheck#1#2{% \setbox\z@\hbox{\m@th$#1#2$}% \setbox\tw@\hbox{\m@th$#1% \widehat{% \vrule\@width\z@\@height\ht\z@ \vrule\@height\z@\@width\wd\z@}$}% \dp\tw@-\ht\z@ \@tempdima\ht\z@ \advance\@tempdima2\ht\tw@ \divide\@tempdima\thr@@ \setbox\tw@\hbox{% \raise\@tempdima\hbox{\scalebox{1}[-1]{\lower\@tempdima\box \tw@}}}% {\ooalign{\box\tw@ \cr \box\z@}}} \makeatother % \mathraisebox{voffset}[height][depth]{something} \makeatletter \NewDocumentCommand\mathraisebox{moom}{% \IfNoValueTF{#2}{\def\@temp##1##2{\raisebox{#1}{$\m@th##1##2$}}}{% \IfNoValueTF{#3}{\def\@temp##1##2{\raisebox{#1}[#2]{$\m@th##1##2$}}% }{\def\@temp##1##2{\raisebox{#1}[#2][#3]{$\m@th##1##2$}}}}% \mathpalette\@temp{#4}} \makeatletter % udots (taken from yhmath) \makeatletter \def\udots{\mathinner{\mkern2mu\raise\p@\hbox{.} \mkern2mu\raise4\p@\hbox{.}\mkern1mu \raise7\p@\vbox{\kern7\p@\hbox{.}}\mkern1mu}} \makeatother %% Fix array \newcommand{\itexarray}[1]{\begin{matrix}#1\end{matrix}} %% \itexnum is a noop \newcommand{\itexnum}[1]{#1} %% Renaming existing commands \newcommand{\underoverset}[3]{\underset{#1}{\overset{#2}{#3}}} \newcommand{\widevec}{\overrightarrow} \newcommand{\darr}{\downarrow} \newcommand{\nearr}{\nearrow} \newcommand{\nwarr}{\nwarrow} \newcommand{\searr}{\searrow} \newcommand{\swarr}{\swarrow} \newcommand{\curvearrowbotright}{\curvearrowright} \newcommand{\uparr}{\uparrow} \newcommand{\downuparrow}{\updownarrow} \newcommand{\duparr}{\updownarrow} \newcommand{\updarr}{\updownarrow} \newcommand{\gt}{>} \newcommand{\lt}{<} \newcommand{\map}{\mapsto} \newcommand{\embedsin}{\hookrightarrow} \newcommand{\Alpha}{A} \newcommand{\Beta}{B} \newcommand{\Zeta}{Z} \newcommand{\Eta}{H} \newcommand{\Iota}{I} \newcommand{\Kappa}{K} \newcommand{\Mu}{M} \newcommand{\Nu}{N} \newcommand{\Rho}{P} \newcommand{\Tau}{T} \newcommand{\Upsi}{\Upsilon} \newcommand{\omicron}{o} \newcommand{\lang}{\langle} \newcommand{\rang}{\rangle} \newcommand{\Union}{\bigcup} \newcommand{\Intersection}{\bigcap} \newcommand{\Oplus}{\bigoplus} \newcommand{\Otimes}{\bigotimes} \newcommand{\Wedge}{\bigwedge} \newcommand{\Vee}{\bigvee} \newcommand{\coproduct}{\coprod} \newcommand{\product}{\prod} \newcommand{\closure}{\overline} \newcommand{\integral}{\int} \newcommand{\doubleintegral}{\iint} \newcommand{\tripleintegral}{\iiint} \newcommand{\quadrupleintegral}{\iiiint} \newcommand{\conint}{\oint} \newcommand{\contourintegral}{\oint} \newcommand{\infinity}{\infty} \newcommand{\bottom}{\bot} \newcommand{\minusb}{\boxminus} \newcommand{\plusb}{\boxplus} \newcommand{\timesb}{\boxtimes} \newcommand{\intersection}{\cap} \newcommand{\union}{\cup} \newcommand{\Del}{\nabla} \newcommand{\odash}{\circleddash} \newcommand{\negspace}{\!} \newcommand{\widebar}{\overline} \newcommand{\textsize}{\normalsize} \renewcommand{\scriptsize}{\scriptstyle} \newcommand{\scriptscriptsize}{\scriptscriptstyle} \newcommand{\mathfr}{\mathfrak} \newcommand{\statusline}[2]{#2} \newcommand{\tooltip}[2]{#2} \newcommand{\toggle}[2]{#2} % Theorem Environments \theoremstyle{plain} \newtheorem{theorem}{Theorem} \newtheorem{lemma}{Lemma} \newtheorem{prop}{Proposition} \newtheorem{cor}{Corollary} \newtheorem*{utheorem}{Theorem} \newtheorem*{ulemma}{Lemma} \newtheorem*{uprop}{Proposition} \newtheorem*{ucor}{Corollary} \theoremstyle{definition} \newtheorem{defn}{Definition} \newtheorem{example}{Example} \newtheorem*{udefn}{Definition} \newtheorem*{uexample}{Example} \theoremstyle{remark} \newtheorem{remark}{Remark} \newtheorem{note}{Note} \newtheorem*{uremark}{Remark} \newtheorem*{unote}{Note} %------------------------------------------------------------------- \begin{document} %------------------------------------------------------------------- \section*{judgment} \hypertarget{context}{}\subsubsection*{{Context}}\label{context} \hypertarget{type_theory}{}\paragraph*{{Type theory}}\label{type_theory} [[!include type theory - contents]] \hypertarget{foundations}{}\paragraph*{{Foundations}}\label{foundations} [[!include foundations - contents]] \hypertarget{judgments}{}\section*{{Judgments}}\label{judgments} \noindent\hyperlink{idea}{Idea}\dotfill \pageref*{idea} \linebreak \noindent\hyperlink{examples}{Examples}\dotfill \pageref*{examples} \linebreak \noindent\hyperlink{in_firstorder_logic}{In first-order logic}\dotfill \pageref*{in_firstorder_logic} \linebreak \noindent\hyperlink{in_type_theory}{In type theory}\dotfill \pageref*{in_type_theory} \linebreak \noindent\hyperlink{hypothetical_and_generic_judgments}{Hypothetical and generic judgments}\dotfill \pageref*{hypothetical_and_generic_judgments} \linebreak \noindent\hyperlink{related_concepts}{Related concepts}\dotfill \pageref*{related_concepts} \linebreak \noindent\hyperlink{references}{References}\dotfill \pageref*{references} \linebreak \hypertarget{idea}{}\subsection*{{Idea}}\label{idea} In [[formal logic]], a \textbf{judgment}, or \textbf{judgement}, is a ``meta-[[proposition]]''; that is, a proposition belonging to the [[meta-language]] (the [[deductive system]] or [[logical framework]]) rather than to the [[object language]]. More specifically, any [[deductive system]] includes, as part of its specification, which strings of symbols are to be regarded as the \emph{judgments}. Some of these symbols may themselves express a [[proposition]] in the object language, but this is not necessarily the case. The interest in judgements is typically in how they may arise as \emph{theorems}, or as \emph{consequences} of other judgements, by way of the [[deduction]] rules in a deductive system. One writes \begin{displaymath} \vdash J \end{displaymath} to mean that $J$ is a judgment that is derivable, i.e. a [[theorem]] of the deductive system. \hypertarget{examples}{}\subsection*{{Examples}}\label{examples} \hypertarget{in_firstorder_logic}{}\subsubsection*{{In first-order logic}}\label{in_firstorder_logic} In [[first-order logic]], a paradigmatic example of a judgement is the judgement that a certain string of symbols is a well-formed [[proposition]]. This is often written as ``$P \;prop$'', where $P$ is a [[metavariable]] standing for a string of symbols that denotes a proposition. Another example of a judgement is the judgement that these symbols form a proposition [[proof|proved]] to be [[true]]. This judgment is often written as ``$P\;true$''. Neither of these judgements is the same thing as the proposition $P$ itself. In particular, the proposition is a statement \emph{in} the logic, while the judgement that the proposition is a proposition, or is provably true, is a statement \emph{about} the logic. However, often people abuse notation and conflate a proposition with the judgment that it is true, writing $P$ instead of $P\;true$. \hypertarget{in_type_theory}{}\subsubsection*{{In type theory}}\label{in_type_theory} The distinction between judgements and [[propositions]] is particularly important in [[intensional type theory]]. The paradigmatic example of a judgment in [[type theory]] is a \emph{typing judgment}. The assertion that a [[term]] $t$ has [[type]] $A$ (written ``$t:A$'') is not a statement \emph{in} the type theory (that is, not something which one could apply logical operators to in the type-theoretic system) but a statement \emph{about} the type theory. Often, type theories include only a particular small set of judgments, such as: \begin{itemize}% \item typing judgments (written $t:A$, as above) \item judgments of typehood (usually written $A \;type$) \item judgments of [[equality]] between typed terms (written say $(t=t'):A$) \end{itemize} (In a type theory with a [[type of types]], judgments of typehood can sometimes be incorporated as a special case of typing judgments, writing $A:Type$ instead of $A\;type$.) These limited sets of judgments are often defined [[inductive definition|inductively]] by giving [[type formation]]/[[term introduction]]/[[term elimination]]- and [[computation rules]] (see [[natural deduction]]) that specify under what hypotheses one is allowed to conclude the given judgment. These inductive definitions can be formalized by choosing a particular [[type theory]] to be the meta-language; usually a very simple type theory suffices (such as a [[dependent type theory]] with only [[dependent product types]]). Such a meta-type-theory is often called a [[logical framework]]. \hypertarget{hypothetical_and_generic_judgments}{}\subsection*{{Hypothetical and generic judgments}}\label{hypothetical_and_generic_judgments} It may happen that a judgment $J$ is only derivable under the assumptions of certain other judgments $J_1,\dots, J_2$. In this case one writes \begin{displaymath} J_1,\dots,J_n \;\vdash J. \end{displaymath} Often, however, it is convenient to incorporate hypotheticality into judgments themselves, so that $J_1,\dots,J_n \;\vdash J$ becomes a single \emph{[[hypothetical judgment]]}. It can then be a consquence of other judgments, or (more importantly) a hypothesis used in concluding other judgments. For instance, in order to conclude the truth of an [[implication]] $\phi\Rightarrow\psi$, we must conclude $\psi$ \emph{assuming} $\phi$; thus the [[introduction rule]] for implication is \begin{displaymath} \frac{\phi \;\vdash\; \psi}{\vdash\; \phi\Rightarrow\psi} \end{displaymath} with a hypothetical judgment as its hypothesis. See [[natural deduction]] for a more extensive discussion. In a [[type theory]], we may also consider the case where the hypotheses $J_1$ are typing judgments of the form $x:A$, where $x$ is a [[variable]], and in which the conclusion judgment $J$ involves these variables as [[free variables]]. For instance, $J$ could be $\phi\;prop$, where $\phi$ is a valid (well-formed) proposition only when $x$ has a specific [[type]] $X$. In this case we have a \emph{[[generic judgement]]}, written \begin{displaymath} (x \colon X) \;\vdash\; (\phi \; prop). \end{displaymath} which expresses that \emph{assuming the hypothesis or [[antecedent]] judgement} that $x$ is of type $X$, as a consequence we have the [[succedent]] judgement that $\phi$ is a proposition. If on the right here we have a typing judgment \begin{displaymath} (x \colon X) \;\vdash\; (t \colon A) \end{displaymath} we have a \emph{[[term in context]]}. For more about the precise relationship between the various meanings of $\vdash$ here, see [[natural deduction]] and [[logical framework]]. While this may seem to be a very basic form of (hypothetical/generic) judgement only, in systems such as [[dependent type theory]] or [[homotopy type theory]], all of [[logic]] and a good bit more is all based on just this. \hypertarget{related_concepts}{}\subsection*{{Related concepts}}\label{related_concepts} \begin{itemize}% \item [[infinite judgment]] \end{itemize} \hypertarget{references}{}\subsection*{{References}}\label{references} Foundational discussion of the notion of \emph{judgement} in [[formal logic]] is in \begin{itemize}% \item [[Per Martin-Löf]], \emph{On the meaning of logical constants and the justifications of the logical laws}, leture series in Siena (1983) (\href{http://docenti.lett.unisi.it/files/4/1/1/6/martinlof4.pdf}{web}) \item [[Per Martin-Löf]], \emph{A path from logic to metaphysics}, talk at \emph{Nuovi problemi della logica e della filosofia della scienza}, Jan 1990 (\href{https://github.com/michaelt/martin-lof/raw/master/pdfs/A-path-from-logic-to-metaphysics-1991.pdf}{pdf}) \end{itemize} More on this is in in sections 2 and 3 of \begin{itemize}% \item [[Frank Pfenning]], Rowan Davies, \emph{A judgemental reconstruction of modal logic} (2000) (\href{http://www.cs.cmu.edu/~fp/papers/mscs00.pdf}{pdf}) \end{itemize} A textbook acccount is in section I.3 of \begin{itemize}% \item [[Robert Harper]], \emph{[[Practical Foundations for Programming Languages]]} \end{itemize} Something called \emph{judgement} (Urteil) appears in \begin{itemize}% \item [[Georg Hegel]], second part, first section, second chapter of \emph{[[Science of Logic]]}. \end{itemize} [[!redirects judgment]] [[!redirects judgments]] [[!redirects judgement]] [[!redirects judgements]] [[!redirects hypothetical judgment]] [[!redirects hypothetical judgments]] [[!redirects hypothetical judgement]] [[!redirects hypothetical judgements]] [[!redirects generic judgment]] [[!redirects generic judgments]] [[!redirects generic judgement]] [[!redirects generic judgements]] \end{document}