diff --git a/spec/alethe_rules.tex b/spec/alethe_rules.tex
index b65e1d19d72c790a7128a83d1259b598257376e6..c9c1b4d31ce0b323202918c8f29d9f941d4cc9d6 100644
--- a/spec/alethe_rules.tex
+++ b/spec/alethe_rules.tex
@@ -20,29 +20,29 @@ to quickly find the definition of rules.
 \begin{xltabular}{\linewidth}{l X}
 \caption{Special rules.}
 \label{rule-tab:special}\\
-	Rule & Description \\
-	\hline
-	\ruleref{assume}   & Repetition of an input assumption. \\
-	\ruleref{hole}     & Placeholder for rules not defined here. \\
-	\ruleref{subproof} & Concludes a subproof and discharges local assumptions. \\
+  Rule & Description \\
+  \hline
+  \ruleref{assume}   & Repetition of an input assumption. \\
+  \ruleref{hole}     & Placeholder for rules not defined here. \\
+  \ruleref{subproof} & Concludes a subproof and discharges local assumptions. \\
 \end{xltabular}
 
 \begin{xltabular}{\linewidth}{l X}
 \caption{Resolution and related rules.}
 \label{rule-tab:resolution}\\
-	Rule & Description \\
-	\hline
-	\ruleref{resolution} & Chain resolution of two or more clauses. \\
-	\ruleref{th_resolution} & As \proofRule{resolution}, but used by theory solvers. \\
-	\ruleref{tautology} & Simplification of tautological clauses to $\top$. \\
-	\ruleref{contraction} & Removal of duplicated literals. \\
+  Rule & Description \\
+  \hline
+  \ruleref{resolution} & Chain resolution of two or more clauses. \\
+  \ruleref{th_resolution} & As \proofRule{resolution}, but used by theory solvers. \\
+  \ruleref{tautology} & Simplification of tautological clauses to $\top$. \\
+  \ruleref{contraction} & Removal of duplicated literals. \\
 \end{xltabular}
 
 \begin{xltabular}{\linewidth}{l X}
 \caption{Rules introducing tautologies.}
 \label{rule-tab:tautologies}\\
-	Rule & Description \\
-	\hline
+  Rule & Description \\
+  \hline
 \ruleref{true} & $\top$ \\
 \ruleref{false} & $\neg\bot$ \\
 \ruleref{not_not} & $\neg(\neg\neg\varphi), \varphi$ \\
@@ -104,8 +104,8 @@ to quickly find the definition of rules.
 \begin{xltabular}{\linewidth}{l X}
 \caption{Linear arithmetic rules.}
 \label{rule-tab:la-tauts}\\
-	Rule & Description \\
-	\hline
+  Rule & Description \\
+  \hline
 \ruleref{la_generic} & Tautologous disjunction of linear inequalities. \\
 \ruleref{lia_generic} & Tautologous disjunction of linear integer inequalities. \\
 \ruleref{la_disequality} & $t_1 ≈ t_2 \lor \neg (t_1 \leq t_2) \lor \neg (t_2 \leq t_1)$ \\
@@ -123,8 +123,8 @@ to quickly find the definition of rules.
 \begin{xltabular}{\linewidth}{l X}
 \caption{Quantifier handling.}
 \label{rule-tab:quants}\\
-	Rule & Description \\
-	\hline
+  Rule & Description \\
+  \hline
 \ruleref{forall_inst} & Instantiation of a universal variable. \\
 \ruleref{bind} & Renaming of bound variables. \\
 \ruleref{sko_ex} & Skolemization of existential variables. \\
@@ -139,8 +139,8 @@ to quickly find the definition of rules.
 \begin{xltabular}{\linewidth}{l X}
 \caption{Skolemization rules.}
 \label{rule-tab:skos}\\
-	Rule & Description \\
-	\hline
+  Rule & Description \\
+  \hline
 \ruleref{sko_ex} & Skolemization of existential variables. \\
 \ruleref{sko_forall} & Skolemization of universal variables. \\
 \end{xltabular}
@@ -149,8 +149,8 @@ to quickly find the definition of rules.
 \caption{Clausification rules.  These rules can be used to perform propositional
 clausification.}
 \label{rule-tab:clausification}\\
-	Rule & Description \\
-	\hline
+  Rule & Description \\
+  \hline
 \ruleref{and} & And elimination. \\
 \ruleref{not_or} & Elimination of a negated disjunction. \\
 \ruleref{or} & Disjunction to clause. \\
@@ -204,8 +204,8 @@ $\varphi_1 ≈ \varphi_2 , \varphi_1 , \varphi_2$ \\
 \caption{Simplification rules. These rules represent typical operator-level
 simplifications.}
 \label{rule-tab:simplification}\\
-	Rule & Description \\
-	\hline
+  Rule & Description \\
+  \hline
 \ruleref{connective_def} & Definition of the Boolean connectives. \\
 \ruleref{and_simplify} & Simplification of a conjunction. \\
 \ruleref{or_simplify} & Simplification of a disjunction. \\
@@ -236,12 +236,12 @@ simplifications.}
 \begin{AletheX}
 $i$. & \ctxsep & $\varphi$ & \currule \\
 \end{AletheX}
-	where $\varphi$ corresponds up to the orientation of equalities
-	to a formula asserted in the input problem.
-	\ruleparagraph{Remark.}
-	This rule can not be used by the
-	\inlineAlethe{(step }\dots\inlineAlethe{)} command. Instead it corresponds to the dedicated
-	\inlineAlethe{(assume }\dots\inlineAlethe{)} command.
+  where $\varphi$ corresponds up to the orientation of equalities
+  to a formula asserted in the input problem.
+  \ruleparagraph{Remark.}
+  This rule can not be used by the
+  \inlineAlethe{(step }\dots\inlineAlethe{)} command. Instead it corresponds to the dedicated
+  \inlineAlethe{(assume }\dots\inlineAlethe{)} command.
 \end{RuleDescription}
 
 \begin{RuleDescription}{hole}
@@ -400,11 +400,11 @@ each $i$, let $\varphi := \varphi_i$ and $a := a_i$.
 
 \begin{enumerate}
     \item If $\varphi = s_1 > s_2$, then let $\varphi := s_1 \leq s_2$.
-    	If $\varphi = s_1 \geq s_2$, then let $\varphi := s_1 < s_2$.
-    	If $\varphi = s_1 < s_2$, then let $\varphi := s_1 \geq s_2$. 
-    	If $\varphi = s_1 \leq s_2$, then let $\varphi := s_1 > s_2$. This negates
-    	the literal.
-   	\item If $\varphi = \neg (s_1 \bowtie s_2)$, then let $\varphi := s_1 \bowtie s_2$. 
+      If $\varphi = s_1 \geq s_2$, then let $\varphi := s_1 < s_2$.
+      If $\varphi = s_1 < s_2$, then let $\varphi := s_1 \geq s_2$. 
+      If $\varphi = s_1 \leq s_2$, then let $\varphi := s_1 > s_2$. This negates
+      the literal.
+     \item If $\varphi = \neg (s_1 \bowtie s_2)$, then let $\varphi := s_1 \bowtie s_2$. 
     \item Replace $\varphi$ by $\sum_{i=0}^{n}c_i\times{}t_i - \sum_{i=n+1}^{m} c_i\times{}t_i
     \bowtie d$ where $d := d_2 - d_1$.
     \item \label{la_generic:str}Now $\varphi$ has the form $s_1 \bowtie d$. If all
@@ -537,8 +537,8 @@ as for the rule \proofRule{la_generic}.
 \begin{AletheXS}
 \aletheLineSB
 $j$. & \spctx{ $\Gamma, y_1,\dots, y_n,  x_1 \mapsto y_1, \dots ,  x_n \mapsto y_n$}
-	 & \ctxsep & $\varphi ≈ \varphi'$ & ($\dots$) \\
-	 \spsep
+   & \ctxsep & $\varphi ≈ \varphi'$ & ($\dots$) \\
+   \spsep
 $k$. & & \ctxsep & 
     $\forall x_1, \dots, x_n.\varphi ≈ \forall y_1, \dots, y_n. \varphi'$
      & \currule{} \\
@@ -554,8 +554,8 @@ The \currule{} rule skolemizes existential quantifiers.
 \aletheLineS
 $j$. &
 \spctx{$\Gamma, x_1 \mapsto \varepsilon_1, \dots ,  x_n \mapsto \varepsilon_n$}
-	 & \ctxsep &  $\varphi ≈ \psi$ & ($\dots$) \\
-	 \spsep
+   & \ctxsep &  $\varphi ≈ \psi$ & ($\dots$) \\
+   \spsep
 $k$. & & \ctxsep & $\exists x_1, \dots, x_n.\varphi ≈ \psi$ & \currule{} \\
 \end{AletheXS}
 where $\varepsilon_i$ stands for $\varepsilon x_i. (\exists x_{i+1}, \dots,
@@ -569,7 +569,7 @@ The \currule{} rule skolemizes universal quantifiers.
 \aletheLineS
 $j$. & 
 \spctx{$\Gamma, x_1 \mapsto (\varepsilon x_1.\neg\varphi), \dots,  x_n \mapsto (\varepsilon x_n.\neg\varphi)$}
-	 & \ctxsep & $\varphi ≈ \psi$ & ($\dots$) \\
+   & \ctxsep & $\varphi ≈ \psi$ & ($\dots$) \\
  \spsep
 $k$. & & \ctxsep  & $\forall x_1, \dots, x_n.\varphi ≈ \psi$ & \currule{} \\
 \end{AletheXS}
@@ -1080,11 +1080,11 @@ The possible transformations are:
     \item $\bot \rightarrow  \varphi ⇒ \top$
     \item $ \varphi \rightarrow \top ⇒ \top$
     \item $\top \rightarrow  \varphi ⇒  \varphi$
-		\item $ \varphi \rightarrow \bot ⇒ \neg \varphi$
-		\item $ \varphi \rightarrow  \varphi ⇒ \top$
-		\item $\neg \varphi \rightarrow  \varphi ⇒  \varphi$
-		\item $ \varphi \rightarrow \neg \varphi ⇒ \neg \varphi$
-		\item $( \varphi_1\rightarrow \varphi_2)\rightarrow \varphi_2 ⇒  \varphi_1\lor \varphi_2$
+    \item $ \varphi \rightarrow \bot ⇒ \neg \varphi$
+    \item $ \varphi \rightarrow  \varphi ⇒ \top$
+    \item $\neg \varphi \rightarrow  \varphi ⇒  \varphi$
+    \item $ \varphi \rightarrow \neg \varphi ⇒ \neg \varphi$
+    \item $( \varphi_1\rightarrow \varphi_2)\rightarrow \varphi_2 ⇒  \varphi_1\lor \varphi_2$
 \end{itemize}
 \end{RuleDescription}
 
@@ -1122,13 +1122,13 @@ where $\psi$ is the transformed term.
 
 The possible transformations are:
 \begin{itemize}
-	\item $\neg(\varphi_1\rightarrow \varphi_2) ⇒ (\varphi_1 \land \neg \varphi_2)$
-	\item $\neg(\varphi_1\lor \varphi_2) ⇒ (\neg \varphi_1 \land \neg \varphi_2)$
-	\item $\neg(\varphi_1\land \varphi_2) ⇒ (\neg \varphi_1 \lor \neg \varphi_2)$
-	\item $(\varphi_1 \rightarrow (\varphi_2\rightarrow \varphi_3)) ⇒ (\varphi_1\land \varphi_2) \rightarrow \varphi_3$
-	\item $((\varphi_1\rightarrow \varphi_2)\rightarrow \varphi_2)  ⇒ (\varphi_1\lor \varphi_2)$
-	\item $(\varphi_1 \land (\varphi_1\rightarrow \varphi_2)) ⇒ (\varphi_1 \land \varphi_2)$
-	\item $((\varphi_1\rightarrow \varphi_2) \land \varphi_1) ⇒ (\varphi_1 \land \varphi_2)$
+  \item $\neg(\varphi_1\rightarrow \varphi_2) ⇒ (\varphi_1 \land \neg \varphi_2)$
+  \item $\neg(\varphi_1\lor \varphi_2) ⇒ (\neg \varphi_1 \land \neg \varphi_2)$
+  \item $\neg(\varphi_1\land \varphi_2) ⇒ (\neg \varphi_1 \lor \neg \varphi_2)$
+  \item $(\varphi_1 \rightarrow (\varphi_2\rightarrow \varphi_3)) ⇒ (\varphi_1\land \varphi_2) \rightarrow \varphi_3$
+  \item $((\varphi_1\rightarrow \varphi_2)\rightarrow \varphi_2)  ⇒ (\varphi_1\lor \varphi_2)$
+  \item $(\varphi_1 \land (\varphi_1\rightarrow \varphi_2)) ⇒ (\varphi_1 \land \varphi_2)$
+  \item $((\varphi_1\rightarrow \varphi_2) \land \varphi_1) ⇒ (\varphi_1 \land \varphi_2)$
 \end{itemize}
 \end{RuleDescription}
 
@@ -1165,9 +1165,9 @@ The possible transformations are:
     \item $\lsymb{ite}\, \psi      \, t \, t ⇒ t$
     \item $\lsymb{ite}\, \neg \varphi \, t_1 \, t_2 ⇒ \lsymb{ite}\, \varphi \, t_2 \, t_1$
     \item $\lsymb{ite}\, \psi \, (\lsymb{ite}\, \psi\,t_1\,t_2)\, t_3 ⇒
-			\lsymb{ite}\, \psi\, t_1\, t_3$
+      \lsymb{ite}\, \psi\, t_1\, t_3$
     \item $\lsymb{ite}\, \psi \, t_1\, (\lsymb{ite}\, \psi\,t_2\,t_3) ⇒
-			\lsymb{ite}\, \psi\, t_1\, t_3$
+      \lsymb{ite}\, \psi\, t_1\, t_3$
     \item $\lsymb{ite}\, \psi \, \top\, \bot ⇒ \psi$
     \item $\lsymb{ite}\, \psi \, \bot\, \top ⇒ \neg\psi$
     \item $\lsymb{ite}\, \psi \, \top \, \varphi ⇒ \psi\lor\varphi$
@@ -1193,7 +1193,7 @@ variables that can only have one value.
 \begin{AletheXS}
 \aletheLineS
 $j$. & \spctx{$\Gamma, x_{k_1},\dots, x_{k_m},  x_{j_1} \mapsto t_{j_1}, \dots ,  x_{j_o} \mapsto t_{j_o}$}
-	 & \ctxsep & $\varphi ≈ \varphi'$ & ($\dots$) \\
+   & \ctxsep & $\varphi ≈ \varphi'$ & ($\dots$) \\
  \spsep
 $k$. & & \ctxsep  & $Q x_1, \dots, x_n.\varphi ≈ Q x_{k_1}, \dots, x_{k_m}. \varphi'$ & \currule{} \\
 \end{AletheXS}
@@ -1283,9 +1283,9 @@ The possible transformations are:
 \begin{itemize}
   \item $t\, /\, t ⇒ 1$
   \item $t\, /\, 1 ⇒ t$
-	\item $t_1\,  /\,  t_2 ⇒ t_3$
-		if $t_1$ and $t_2$ are constants and $t_3$ is $t_1$
-		divided by $t_2$ according to the semantic of the current theory.
+  \item $t_1\,  /\,  t_2 ⇒ t_3$
+    if $t_1$ and $t_2$ are constants and $t_3$ is $t_1$
+    divided by $t_2$ according to the semantic of the current theory.
 \end{itemize}
 \end{RuleDescription}
 
@@ -1305,12 +1305,12 @@ The possible transformations are:
     \item $t_1\times\cdots\times t_n ⇒ 0$ if any
     $t_i$ is $0$.
     \item $t_1\times\cdots\times t_n ⇒
-			c \times t_{k_1}\times\cdots\times t_{k_n}$ where $c$
-			is the product of the constants of $t_1, \dots, t_n$ and
-			$t_{k_1}, \dots, t_{k_n}$ is $t_1, \dots, t_n$
-			with the constants removed.
+      c \times t_{k_1}\times\cdots\times t_{k_n}$ where $c$
+      is the product of the constants of $t_1, \dots, t_n$ and
+      $t_{k_1}, \dots, t_{k_n}$ is $t_1, \dots, t_n$
+      with the constants removed.
     \item $t_1\times\cdots\times t_n ⇒
-			t_{k_1}\times\cdots\times t_{k_n}$: same as above if $c$ is $1$.
+      t_{k_1}\times\cdots\times t_{k_n}$: same as above if $c$ is $1$.
 \end{itemize}
 \end{RuleDescription}
 
@@ -1360,13 +1360,13 @@ The possible transformations are:
     \item $t_1+\cdots+t_n ⇒ c$ where all
     $t_i$ are constants and $c$ is their sum.
     \item $t_1+\cdots+t_n ⇒
-			c + t_{k_1}+\cdots+t_{k_n}$ where $c$
-			is the sum of the constants of $t_1, \dots, t_n$ and
-			$t_{k_1}, \dots, t_{k_n}$ is $t_1, \dots, t_n$
-			with the constants removed.
+      c + t_{k_1}+\cdots+t_{k_n}$ where $c$
+      is the sum of the constants of $t_1, \dots, t_n$ and
+      $t_{k_1}, \dots, t_{k_n}$ is $t_1, \dots, t_n$
+      with the constants removed.
     \item $t_1+\cdots+t_n ⇒
-			t_{k_1}+\cdots+t_{k_n}$: same as above if $c$ is
-			$0$.
+      t_{k_1}+\cdots+t_{k_n}$: same as above if $c$ is
+      $0$.
 \end{itemize}
 \end{RuleDescription}
 
@@ -1405,16 +1405,16 @@ $i_1$. & $\Gamma$ & \ctxsep & $t_{1} ≈ s_{1}$ & ($\dots$) \\
 $i_n$. & $\Gamma$ & \ctxsep & $t_{n} ≈ s_{n}$ & ($\dots$) \\
 \aletheLineS
 $j$. & \spctx{$\Gamma, x_1 \mapsto s_1, \dots,  x_n \mapsto s_n$}
-	 & \ctxsep &  $u ≈ u'$ & ($\dots$) \\
+   & \ctxsep &  $u ≈ u'$ & ($\dots$) \\
 \spsep
 $k$. & $\Gamma$ & \ctxsep & 
      $(\lsymb{let}\,x_1 = t_1,\, \dots,\, x_n = t_n\,\lsymb{in}\, u) ≈ u'$
      & (\currule{}\;$i_1$, \dots, $i_n$) \\
 \end{AletheXS}
 
-	The premise $i_1, \dots, i_n$ must be in the same subproof as
-	the \currule{} step.  If for $t_i≈ s_i$ the $t_i$ and $s_i$
-	are syntactically equal, the premise
+  The premise $i_1, \dots, i_n$ must be in the same subproof as
+  the \currule{} step.  If for $t_i≈ s_i$ the $t_i$ and $s_i$
+  are syntactically equal, the premise
   is skipped.
 \end{RuleDescription}
 
@@ -1515,7 +1515,7 @@ The term $t$ (the formula $\varphi$) contains the $\lsymb{ite}$ operator.
 Let $s_1, \dots, s_n$ be the terms starting with $\lsymb{ite}$, i.e.
 $s_i := \lsymb{ite}\,\psi_i\,r_i\,r'_i$, then $u_i$ has the form
 \[
-	\lsymb{ite}\,\psi_i\,(s_i ≈ r_i)\,(s_i ≈ r'_i)
+  \lsymb{ite}\,\psi_i\,(s_i ≈ r_i)\,(s_i ≈ r'_i)
 \]
 The term $t'$ is equal to the term $t$ up to the
 reordering of equalities where one argument is an $\lsymb{ite}$
diff --git a/spec/spec.tex b/spec/spec.tex
index e0547d5994fb15cb25702ebf0a4578d33fa3389f..aeb5c6e4ab6b1ee403bd9ac8976065a101d155d9 100644
--- a/spec/spec.tex
+++ b/spec/spec.tex
@@ -89,7 +89,7 @@
 \newcolumntype{Y}{>{\centering\arraybackslash}X}
 
 \newcommand{\ruleTypeImpl}[1]{%
-	\microtypesetup{tracking=false}\textsf{#1}\microtypesetup{tracking=true}%
+  \microtypesetup{tracking=false}\textsf{#1}\microtypesetup{tracking=true}%
 }
 \def\ruleType#1{\ruleTypeImpl{\detokenize{#1}}} % non linked rule (for examples)
 \def\proofRule#1{\hyperref[rule:\detokenize{#1}]{\ruleTypeImpl{\detokenize{#1}}}} % linked rule
@@ -199,10 +199,10 @@ break
 \and Hans-Jörg Schurr\textsuperscript{4}}
 \date{}
 \publishers{
-	\textsuperscript{1} Universidade Federal de Minas Gerais, Brazil\\
-	\textsuperscript{2} Albert-Ludwig-Universität Freiburg, Germany\\
-	\textsuperscript{3} Université de Liège, Belgium\\
-	\textsuperscript{4} University of Lorraine, CNRS, Inria, and LORIA, Nancy, France\\
+  \textsuperscript{1} Universidade Federal de Minas Gerais, Brazil\\
+  \textsuperscript{2} Albert-Ludwig-Universität Freiburg, Germany\\
+  \textsuperscript{3} Université de Liège, Belgium\\
+  \textsuperscript{4} University of Lorraine, CNRS, Inria, and LORIA, Nancy, France\\
 }
 
 
@@ -583,7 +583,7 @@ variable.
 \spsep
 5.& & \ctxsep & $\forall x.\,(P\,x) ≈ \forall y.\,(P\,y)$ & $\proofRule{bind}$ \\
 6.& & \ctxsep &
-	    $\neg(\forall x.\,(P\,x) ≈ \forall y.\,(P\,y))$, $\neg(\forall x.\,(P\,x)), (\forall y.\,(P\,y))$
+      $\neg(\forall x.\,(P\,x) ≈ \forall y.\,(P\,y))$, $\neg(\forall x.\,(P\,x)), (\forall y.\,(P\,y))$
     & $\proofRule{equiv_pos2}$ \\
 7.& &\ctxsep & $\bot$ & $(\proofRule{resolution}\,1, 2, 5, 6)$ \\
 \end{AletheS}
@@ -630,7 +630,7 @@ logic and term language, it also uses commands to structure the proof.
 An Alethe proof is a list of commands.
 
 \begin{figure}[t]
-	  \begin{AletheVerb}
+    \begin{AletheVerb}
 (assume h1 (not (p a)))
 (assume h2 (forall ((z1 U)) (forall ((z2 U)) (p z2))))
 ...
@@ -650,7 +650,7 @@ An Alethe proof is a list of commands.
 (step t16 (cl (not (forall ((vr5 U)) (p vr5))) (p a))
           :rule or :premises (t15))
 (step t17 (cl) :rule resolution :premises (t16 h1 t14))
-	  \end{AletheVerb}
+    \end{AletheVerb}
 \caption{Example proof output. Assumptions are
   introduced;   a subproof renames bound variables; the proof finishes with
   instantiation and resolution steps.}
@@ -660,7 +660,7 @@ An Alethe proof is a list of commands.
 
 \begin{figure}[t]
 \[
-	\begin{array}{r c l}
+  \begin{array}{r c l}
  \grNT{proof}           &\grRule & \grNT{proof\_command}^{*} \\
  \grNT{proof\_command}  &\grRule & \textAlethe{(assume}\; \grNT{symbol}\; \grNT{proof\_term}\,\textAlethe{)} \\
                         &\grOr   & \textAlethe{(step}\; \grNT{symbol}\; \grNT{clause}
@@ -681,10 +681,10 @@ An Alethe proof is a list of commands.
  \grNT{context\_annotation}  &\grRule & \textAlethe{:args}\,\textAlethe{(}\,\grNT{context\_assignment}^{+}\,\textAlethe{)}  \\
  \grNT{context\_assignment}  &\grRule & \textAlethe{(}    \,\grNT{sorted\_var}\,\textAlethe{)}  \\
                              & \grOr  & \textAlethe{(:=}\, \grNT{symbol}\;\grNT{proof\_term}\,\textAlethe{)} \\
-	\end{array}
-	\]
-	\caption{The proof grammar.}
-	\label{fig:grammar}
+  \end{array}
+  \]
+  \caption{The proof grammar.}
+  \label{fig:grammar}
 \end{figure}
 
 
@@ -840,7 +840,7 @@ expressed as a concrete proof.
      system/.style={draw, thin, rounded corners},
 }
 
-	\begin{figure}[t]
+  \begin{figure}[t]
 \center
 \begin{tikzpicture}[node distance=2cm, auto,>=latex', thick,scale=0.8]
     \node[solver] (unsat) {\textsf{Unsat mode}};
@@ -926,18 +926,18 @@ no \inlineAlethe{define-fun} commands are issued, and the constants are expanded
 \paragraph{Implicit Transformations}
 Overall, the following aspects are treated implicitly by Alethe.
 \begin{itemize}
-	\item Symmetry of equalities that are not top-most equalities in steps with
-	      non-empty context.
-	\item The order of literals in the clauses.
-	\item The unfolding of names introduced by
-	   \inlineAlethe{(!}\,$t$\,\inlineAlethe{:named }\;$s$\,\inlineAlethe{)}.
-	\item The removal of other {\smtlib} annotations of the form
-	   \inlineAlethe{(!}\,$t$\,\dots\,\inlineAlethe{)}.
-	\item The unfolding of function symbols introduced by
-	\inlineAlethe{define-fun}.\footnote{For {\verit} this is only used when the user
-	introduces {\verit} to print Skolem terms as defined functions. User defined
-	functions in the input problem are not supported by {\verit} in proof production
-	mode.}
+  \item Symmetry of equalities that are not top-most equalities in steps with
+        non-empty context.
+  \item The order of literals in the clauses.
+  \item The unfolding of names introduced by
+     \inlineAlethe{(!}\,$t$\,\inlineAlethe{:named }\;$s$\,\inlineAlethe{)}.
+  \item The removal of other {\smtlib} annotations of the form
+     \inlineAlethe{(!}\,$t$\,\dots\,\inlineAlethe{)}.
+  \item The unfolding of function symbols introduced by
+  \inlineAlethe{define-fun}.\footnote{For {\verit} this is only used when the user
+  introduces {\verit} to print Skolem terms as defined functions. User defined
+  functions in the input problem are not supported by {\verit} in proof production
+  mode.}
 \end{itemize}
 
 Alethe proofs contain steps for other aspects that are commonly left implicit, such
@@ -1005,7 +1005,7 @@ It is easy to calculate the context of the first-innermost subproof.
 \begin{definition}[Calculated Context]
   Let $[C_{\mathit{start}}, \dots, C_{\mathit{end}}]$ be
   the first-innermost subproof of $P$.
-	For $\mathit{start} \leq i < \mathit{end}$, let
+  For $\mathit{start} \leq i < \mathit{end}$, let
   $A_1, \dots, A_m$ be the anchors among $C_1, \dots, C_{i-1}$.
 
   The \index{context!calculated}calculated context of $C_i$ is the context
@@ -1039,9 +1039,9 @@ in the subproof.  The conditions of each rule are listed in
 Section~\ref{apx:rules}.
 
 \begin{definition}[Valid First-Innermost Subproof]
-	Let $[C_{\mathit{start}}, \dots, C_{\mathit{end}}]$
-	be the first-innermost subproof of $P$.
-	The subproof is \index{subproof!valid}{\em valid} if
+  Let $[C_{\mathit{start}}, \dots, C_{\mathit{end}}]$
+  be the first-innermost subproof of $P$.
+  The subproof is \index{subproof!valid}{\em valid} if
   \begin{itemize}
     \item all steps $C_i$ with $\mathit{start} < i <
     \mathit{end}$ only use premises $C_j$ with $\mathit{start} <
@@ -1049,7 +1049,7 @@ Section~\ref{apx:rules}.
     \item all $C_i$ that are steps adhere to the conditions of their
     rule under the calculated context of $C_i$,
     \item the step $C_{\mathit{end}}$
-		adheres to the conditions of its
+    adheres to the conditions of its
     rule under the calculated context of $C_{\mathit{start}}$.
   \end{itemize}
 \end{definition}
@@ -1102,19 +1102,19 @@ Since this proof contains no subproof, it is also $P_{\mathit{last}}$.
 
 
 \begin{definition}[Well-Formed Proof]
-	\label{def:well_formed_proof}
+  \label{def:well_formed_proof}
   The Alethe proof $P$ is \index{proof!well-formed}well-formed
   if every step uses a unique index and $P_{\mathit{last}}$
   contains no anchor or step that uses a concluding rule.
 \end{definition}
 
 \begin{definition}[Valid Alethe Proof]
-	The proof $P$ is a \index{proof!valid}{\em valid Alethe proof} if
+  The proof $P$ is a \index{proof!valid}{\em valid Alethe proof} if
   \begin{itemize}
-  	\item $P$\, is well-formed,
-  	\item $P$\, does not contain any step that uses the \proofRule{hole} rule,
+    \item $P$\, is well-formed,
+    \item $P$\, does not contain any step that uses the \proofRule{hole} rule,
     \item $P_{\mathit{last}}$ contains a step that has the empty clause as its conclusion,
-		\item the first-innermost subproof of every $P_i$, $i < \mathit{last}$ is valid,
+    \item the first-innermost subproof of every $P_i$, $i < \mathit{last}$ is valid,
     \item all steps $C_i$ in $P_{\mathit{last}}$ only use premises
           $C_j$ in $P_{\mathit{last}}$ with $1 \leq j < i$,
     \item all steps $C_i$ in $P_{\mathit{last}}$ adhere to the conditions of their
@@ -1172,8 +1172,8 @@ According to this definition, a metaterm is either a boxed term, a
 The annotation $\groundbox{$t$}$ delimits terms from the context, a simple
 λ-abstraction is used to express fixed variables, and the
 application expresses simulations substitution of $n$ terms.\footnote{
-	The box annotation used here is unrelated to the boxes
-	within the SMT solver discussed in the introduction.}
+  The box annotation used here is unrelated to the boxes
+  within the SMT solver discussed in the introduction.}
 
 We use $=_{\alpha\beta}$ to denote syntactic equivalence modulo
 α-equivalence and β-reduction.
@@ -1296,13 +1296,13 @@ In this section we will address the soundness of concrete Alethe
 proofs.
 
 \begin{theorem}[Soundness of Concrete Alethe Proofs]
-	\label{thm:sound}
-	If there is a valid Alethe proof $P = [C_1, \dots, C_n]$ that has the formulas
-	$\varphi_1, \dots, \varphi_m$ as the conclusions of the outermost \proofRule{assume}
-	steps, then
-	\[
-	\varphi_1, \dots, \varphi_m \vDash \bot.
-	\]
+  \label{thm:sound}
+  If there is a valid Alethe proof $P = [C_1, \dots, C_n]$ that has the formulas
+  $\varphi_1, \dots, \varphi_m$ as the conclusions of the outermost \proofRule{assume}
+  steps, then
+  \[
+  \varphi_1, \dots, \varphi_m \vDash \bot.
+  \]
 \end{theorem}
 
 Here, $\vDash$ represents
@@ -1321,7 +1321,7 @@ We start with simple subproofs with empty contexts and without
 nested subproofs.
 
 \begin{lemma}
-	\label{lem:sound_subproof}
+  \label{lem:sound_subproof}
   Let $P$\, be a proof that contains a valid first-innermost subproof where
   $C_{\mathit{end}}$ is a \proofRule{subproof} step.  Let
   $\psi$ be the conclusion of $C_{\mathit{end}}$.
@@ -1359,22 +1359,22 @@ nested subproofs.
 
   The step $C_{\mathit{end}-1}$ is the last step of the subproof that
   does not use a concluding rule.
-	At this step we have $V_{\mathit{end}-1} \vDash \psi_{\mathit{end}-1}$.
-	Since $C_{\mathit{end}}$ is not an \proofRule{assume} step, the
-	set $V_{\mathit{end}-1} = \{\varphi_1, \dots, \varphi_m\}$ contains
-	all assumptions in the subproof.
-	By the deduction theorem we get
-	\[
-	\vDash \varphi_1 \land \cdots \land \varphi_m → \psi_{\mathit{end}-1}.
-	\]
-	This can be transformed into the clause
-	\[
-	\vDash \neg\varphi_1, \cdots, \neg\varphi_m, l_1, \dots, l_o.
-	\]
-	where $l_1, \dots, l_o$ are the literals of $\psi_{\mathit{end}-1}$.
-	This clause is exactly the conclusion of the 
-	step $C_{\mathit{end}}$
-	according to the definition of the \proofRule{subproof} rule.
+  At this step we have $V_{\mathit{end}-1} \vDash \psi_{\mathit{end}-1}$.
+  Since $C_{\mathit{end}}$ is not an \proofRule{assume} step, the
+  set $V_{\mathit{end}-1} = \{\varphi_1, \dots, \varphi_m\}$ contains
+  all assumptions in the subproof.
+  By the deduction theorem we get
+  \[
+  \vDash \varphi_1 \land \cdots \land \varphi_m → \psi_{\mathit{end}-1}.
+  \]
+  This can be transformed into the clause
+  \[
+  \vDash \neg\varphi_1, \cdots, \neg\varphi_m, l_1, \dots, l_o.
+  \]
+  where $l_1, \dots, l_o$ are the literals of $\psi_{\mathit{end}-1}$.
+  This clause is exactly the conclusion of the 
+  step $C_{\mathit{end}}$
+  according to the definition of the \proofRule{subproof} rule.
 \end{proof}
 
 \noindent
@@ -1407,7 +1407,7 @@ subproofs with contexts.  This is slightly complicated by the
   $C_{\mathit{start}}$, and let $\Gamma$ be the calculated context
   of $C_{\mathit{start}}$.
   $\Gamma' = \Gamma, c_1, \dots, c_n$.
-	is the calculated context of the steps in the subproof after
+  is the calculated context of the steps in the subproof after
   $C_{\mathit{start}}$.
 
   The step $C_{\mathit{end}}$ is a step
@@ -1461,45 +1461,45 @@ a valid, concrete Alethe proof is sound. That is, we can show
 Theorem~\ref{thm:sound}.
 
 \begin{proof}
-	Since $P =[C_1, \dots, C_n]$ is valid, all steps that do not use the
-	\proofRule{hole} rule adhere to their rule.  Since we assume that the
-	abstract notation and the rules are sound, we only have to
-	worry about the steps using the \proofRule{hole} rule.
-	Those should be sound, i.e., for a \proofRule{hole} step with the conclusion
-	$\psi$, premises $V$, and context $\Gamma$
-	the judgment $V \vDash \Gamma \vartriangleright \psi$ must hold.
-
-	Since $P$\, is a valid proof there is a sequence
-	$[P_0, \dots, P_{\mathit{last}}]$ as discussed in Section~\ref{sec:alethe:semantic}.
-	For $i < \mathit{last}$, $E(P_i) = P_{i+1}$ replaces the
-	first-innermost subproof in $P_i$ by a hole with the conclusion
-	$\psi$.  Furthermore, the context of the introduced hole
-	corresponds to the context $\Gamma$ of the start of the subproof.
-	Since $P$ is a valid proof, the first-innermost subproof eliminated by $E$ is
-	always valid.
-	Therefore,
-	we can apply Lemma~\ref{lem:sound_subproof}
-	or Lemma~\ref{lem:sound_subproof_context} to conclude that the hole introduced
-	by $E$ is sound.
-
-	Since $P_0$ does not contain any holes, the holes in each proof
-	$P_i$ are all introduced by innermost-first subproof elimination.
-	Therefore, they are sound. In consequence, all holes in $P_{\mathit{last}}$ are
-	sound and we can perform the same
-	argument as
-	in the proof of Lemma~\ref{lem:sound_subproof} to the proof
-	$P_{\mathit{last}}$.
-
-	Let $j$ be the index of the step in $P_{\mathit{last}}$ that concludes
-	with the empty clause.
-	Let $\mathit{start} = 1$
-	and $\mathit{end} = j$ in the argument of Lemma~\ref{lem:sound_subproof}.
-	This shows that $V \vDash \bot$, where $V$ is the
-	conclusion of the \proofRule{assume} steps in the sublist $[C_1, \dots, C_j]$
-	of $P_{\mathit{last}}$.  We can weaken
-	this by adding the conclusions of the \proofRule{assume} steps in
-	$[C_j, \dots, C_n]$ of $P_{\mathit{last}}$
-	to get $\varphi_1, \dots, \varphi_m \vDash \bot$.
+  Since $P =[C_1, \dots, C_n]$ is valid, all steps that do not use the
+  \proofRule{hole} rule adhere to their rule.  Since we assume that the
+  abstract notation and the rules are sound, we only have to
+  worry about the steps using the \proofRule{hole} rule.
+  Those should be sound, i.e., for a \proofRule{hole} step with the conclusion
+  $\psi$, premises $V$, and context $\Gamma$
+  the judgment $V \vDash \Gamma \vartriangleright \psi$ must hold.
+
+  Since $P$\, is a valid proof there is a sequence
+  $[P_0, \dots, P_{\mathit{last}}]$ as discussed in Section~\ref{sec:alethe:semantic}.
+  For $i < \mathit{last}$, $E(P_i) = P_{i+1}$ replaces the
+  first-innermost subproof in $P_i$ by a hole with the conclusion
+  $\psi$.  Furthermore, the context of the introduced hole
+  corresponds to the context $\Gamma$ of the start of the subproof.
+  Since $P$ is a valid proof, the first-innermost subproof eliminated by $E$ is
+  always valid.
+  Therefore,
+  we can apply Lemma~\ref{lem:sound_subproof}
+  or Lemma~\ref{lem:sound_subproof_context} to conclude that the hole introduced
+  by $E$ is sound.
+
+  Since $P_0$ does not contain any holes, the holes in each proof
+  $P_i$ are all introduced by innermost-first subproof elimination.
+  Therefore, they are sound. In consequence, all holes in $P_{\mathit{last}}$ are
+  sound and we can perform the same
+  argument as
+  in the proof of Lemma~\ref{lem:sound_subproof} to the proof
+  $P_{\mathit{last}}$.
+
+  Let $j$ be the index of the step in $P_{\mathit{last}}$ that concludes
+  with the empty clause.
+  Let $\mathit{start} = 1$
+  and $\mathit{end} = j$ in the argument of Lemma~\ref{lem:sound_subproof}.
+  This shows that $V \vDash \bot$, where $V$ is the
+  conclusion of the \proofRule{assume} steps in the sublist $[C_1, \dots, C_j]$
+  of $P_{\mathit{last}}$.  We can weaken
+  this by adding the conclusions of the \proofRule{assume} steps in
+  $[C_j, \dots, C_n]$ of $P_{\mathit{last}}$
+  to get $\varphi_1, \dots, \varphi_m \vDash \bot$.
 \end{proof}
 
 
@@ -1561,8 +1561,8 @@ is used. It produces a formula of the form $(\neg \forall \bar
 x_n.\,\varphi) \lor \varphi[\bar t_n]$, where $\varphi$ is
 a term containing the free variables $\bar x_n$, and for each $i$ the
 ground term $t_i$ is a new term with the same sort as $x_i$.\footnote{
-	For historical reasons, \proofRule{forall} has a unit clause with a disjunction
-	as its conclusion and not the clause $(\neg \forall \bar x_n.\,\varphi), \varphi[\bar t_n]$.
+  For historical reasons, \proofRule{forall} has a unit clause with a disjunction
+  as its conclusion and not the clause $(\neg \forall \bar x_n.\,\varphi), \varphi[\bar t_n]$.
 }
 
 The arguments of a \proofRule{forall_inst} step is the list $(x_1 , t_1),
@@ -1575,7 +1575,7 @@ Existential quantifiers are handled by skolemization.
 \paragraph{Linear Arithmetic}
 Proofs for linear arithmetic use a number of straightforward rules,
 such as \proofRule{la_totality} ($t_1 \leq t_2 \lor t_2 \leq t_1$)\footnote{
-	This rule also has a unit clause with a disjunction as its conclusion.}
+  This rule also has a unit clause with a disjunction as its conclusion.}
 and the main rule \proofRule{la_generic}.  The conclusion of an
 \proofRule{la_generic} step is a tautology $\neg \varphi_1, \neg
 \varphi_2, \dots, \neg \varphi_n$ where the $\varphi_i$ are linear