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\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*{infinity-Lie algebroid-valued differential form} \hypertarget{context}{}\subsubsection*{{Context}}\label{context} \hypertarget{lie_theory}{}\paragraph*{{$\infty$-Lie theory}}\label{lie_theory} [[!include infinity-Lie theory - contents]] \hypertarget{chernweil_theory}{}\paragraph*{{$\infty$-Chern-Weil theory}}\label{chernweil_theory} [[!include infinity-Chern-Weil theory - contents]] \hypertarget{contents}{}\section*{{Contents}}\label{contents} \noindent\hyperlink{idea}{Idea}\dotfill \pageref*{idea} \linebreak \noindent\hyperlink{definition}{Definition}\dotfill \pageref*{definition} \linebreak \noindent\hyperlink{Properties}{Properties}\dotfill \pageref*{Properties} \linebreak \noindent\hyperlink{curvature_characteristics}{Curvature characteristics}\dotfill \pageref*{curvature_characteristics} \linebreak \noindent\hyperlink{InfGaugeTrafo}{1-Morphisms: integration of infinitesimal gauge transformations}\dotfill \pageref*{InfGaugeTrafo} \linebreak \noindent\hyperlink{examples}{Examples}\dotfill \pageref*{examples} \linebreak \noindent\hyperlink{lie_algebra_valued_1forms}{Lie algebra valued 1-forms}\dotfill \pageref*{lie_algebra_valued_1forms} \linebreak \noindent\hyperlink{lie_2algebra_valued_forms}{Lie 2-algebra valued forms}\dotfill \pageref*{lie_2algebra_valued_forms} \linebreak \noindent\hyperlink{ordinary_forms_and_the_de_rham_complex}{Ordinary $n$-forms and the de Rham complex}\dotfill \pageref*{ordinary_forms_and_the_de_rham_complex} \linebreak \noindent\hyperlink{supergravity_fields}{Supergravity fields}\dotfill \pageref*{supergravity_fields} \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} For $\mathfrak{g}$ an [[∞-Lie algebra]] (or more generally [[∞-Lie algebroid]]), the \textbf{$\infty$-groupoid of $\mathfrak{g}$-valued forms} is the [[∞-groupoid]] whose \begin{itemize}% \item [[object]]s are [[differential forms]] with values in $\mathfrak{g}$; \item [[morphism]]s are [[gauge transformation]]s between these; \item [[k-morphisms]] are order $k$ higher gauge transformations. \end{itemize} This naturally refines to a non-[[concrete sheaf|concrete]] [[∞-Lie groupoid]] whose $U$-parameterized smooth families of objects are [[∞-Lie algebroid]]-valued [[differential form]]s on $Z$. A [[cocycle]] with coefficients in this is a [[connection on an ∞-bundle]]. For an introduction see the section at [[∞-Chern-Weil theory introduction]]. \hypertarget{definition}{}\subsection*{{Definition}}\label{definition} For $X$ a [[smooth manifold]] and $\mathfrak{g}$ an [[∞-Lie algebra]] or more generally an [[∞-Lie algebroid]], a \textbf{$\infty$-Lie algebroid valued differential form} on $X$ is a morphism of [[dg-algebra]]s \begin{displaymath} \Omega^\bullet(X) \leftarrow W(\mathfrak{g}) : A \end{displaymath} from the [[Weil algebra]] of $\mathfrak{g}$ to the [[de Rham complex]] of $X$. Dually this is a morphism of [[∞-Lie algebroid]]s \begin{displaymath} A : T X \to inn(\mathfrak{g}) \end{displaymath} from the [[tangent Lie algebroid]] to the [[Weil algebra|inner automorphism ∞-Lie algebra]]. Its [[curvature]] is the composite of morphisms of [[graded vector space]]s \begin{displaymath} \Omega^\bullet(X) \stackrel{A}{\leftarrow} W(\mathfrak{g}) \stackrel{F_{(-)}}{\leftarrow} \wedge^1 \mathfrak{g}^* : F_{A} \,. \end{displaymath} Precisely if the curvatures vanish does the morphism factor through the [[Chevalley-Eilenberg algebra]] $W(\mathfrak{g}) \to CE(\mathfrak{g})$. \begin{displaymath} (F_A = 0) \;\;\Leftrightarrow \;\; \left( \itexarray{ && CE(\mathfrak{g}) \\ & {}^{\mathllap{\exists A_{flat}}}\swarrow & \uparrow \\ \Omega^\bullet(X) &\stackrel{A}{\leftarrow}& W(\mathfrak{g}) } \right) \end{displaymath} in which case we call $A$ \textbf{flat}. The [[curvature characteristic forms]] of $A$ are the composite \begin{displaymath} \Omega^\bullet(X) \stackrel{A}{\leftarrow} W(\mathfrak{g}) \stackrel{\langle F_{(-)} \rangle}{\leftarrow} inv(\mathfrak{g}) : \langle F_A\rangle \,, \end{displaymath} where $inv(\mathfrak{g}) \to W(\mathfrak{g})$ is the inclusion of the [[invariant polynomial]]s. \begin{defn} \label{}\hypertarget{}{} For $U$ a [[smooth manifold]], the \textbf{$\infty$-groupoid of $\mathfrak{g}$-valued forms is the [[Kan complex]]} \begin{displaymath} \exp(\mathfrak{g})_{conn}(U) : [k] \mapsto \left\{ \Omega^\bullet(U \times \Delta^k) \stackrel{A}{\leftarrow} W(\mathfrak{g}) \;\; | \;\; \forall v \in \Gamma(T \Delta^k) : \iota_v F_A = 0 \right\} \end{displaymath} whose [[k-morphism]]s are $\mathfrak{g}$-valued forms $A$ on $U \times \Delta^k$ with sitting instants, and with the property that their [[curvature]] vanishes on vertical vectors. The canonical morphism \begin{displaymath} \exp(\mathfrak{g})_{conn} \to \exp(\mathfrak{g}) \end{displaymath} to the untruncated [[Lie integration]] of $\mathfrak{g}$ is given by restriction of $A$ to [[vertical differential form]]s (see below). \end{defn} \begin{remark} \label{}\hypertarget{}{} Here we are thinking of $U \times \Delta^k \to U$ as a trivial [[bundle]]. The \emph{first} [[Ehresmann connection|Ehresmann condition]] will be identified with the conditions on lifts $\nabla$ in [[∞-anafunctor]]s \begin{displaymath} \itexarray{ && \exp(\mathfrak{g})_{conn} \\ & {}^{\mathllap{\nabla}}\nearrow & \downarrow \\ C(U) &\stackrel{g}{\to}& \exp(\mathfrak{g}) \\ \downarrow^{\mathrlap{\simeq}} \\ X } \end{displaymath} that define [[connections on ∞-bundles]]. More on this in the \hyperlink{Properties}{Properties}-section below. \end{remark} \hypertarget{Properties}{}\subsection*{{Properties}}\label{Properties} \hypertarget{curvature_characteristics}{}\subsubsection*{{Curvature characteristics}}\label{curvature_characteristics} \begin{prop} \label{}\hypertarget{}{} For $A \in \exp(\mathfrak{g})_{conn}(U,[k])$ a $\mathfrak{g}$-valued form on $U \times \Delta^k$ and for $\langle - \rangle \in W(\mathfrak{g})$ any [[invariant polynomial]], the corresponding [[curvature characteristic form]] $\langle F_A \rangle \in \Omega^\bullet(U \times \Delta^k)$ descends down to $U$. \end{prop} \begin{proof} It is sufficient to show that for all $v \in \Gamma(T \Delta^k)$ we have \begin{enumerate}% \item $\iota_v \langle F_A \rangle = 0$; \item $\mathcal{L}_v \langle F_A \rangle = 0$. \end{enumerate} The first condition is evidently satisfied if already $\iota_v F_A = 0$. The second condition follows with [[Cartan calculus]] and using that $d_{dR} \langle F_A\rangle = 0$: \begin{displaymath} \mathcal{L}_v \langle F_A \rangle = d \iota_v \langle F_A \rangle + \iota_v d \langle F_A \rangle = 0 \,. \end{displaymath} \end{proof} \begin{remark} \label{}\hypertarget{}{} For a general $\infty$-Lie algebra $\mathfrak{g}$ the curvature forms $F_A$ themselves are not closed, hence requiring them to have no component along the simplex does not imply that they descend. This is different for abelian $\infty$-Lie algebras: for them the curvature forms themselves are already closed, and hence are themselves already curvature characteristics that do descent. \end{remark} It is useful to organize the $\mathfrak{g}$-valued form $A$, together with its restriction $A_{vert}$ to [[vertical differential form]]s and with its [[curvature characteristic form]]s in the [[commuting diagram]] (following \emph{\href{Weil+algebra#CharacterizationInSmoothTopos}{Weil algebra -- Characterization in the smooth infinity-topos}}) \begin{displaymath} \itexarray{ \Omega^\bullet(U \times \Delta^k)_{vert} &\stackrel{A_{vert}}{\leftarrow}& CE(\mathfrak{g}) &&& gauge\;transformation \\ \uparrow && \uparrow \\ \Omega^\bullet(U \times \Delta^k) &\stackrel{A}{\leftarrow}& W(\mathfrak{g}) &&& \mathfrak{g}-valued\;form \\ \uparrow && \uparrow \\ \Omega^\bullet(U) &\stackrel{\langle F_A\rangle}{\leftarrow}& inv(\mathfrak{g}) &&& curvature\;characteristic\;forms } \end{displaymath} in [[dgAlg]]. The commutativity of this diagram is implied by $\iota_v F_A = 0$. \begin{defn} \label{}\hypertarget{}{} Write $\exp(\mathfrak{g})_{CW}(U)$ for the $\infty$-groupoid of $\mathfrak{g}$-valued forms fitting into such diagrams. \begin{displaymath} \exp(\mathfrak{g})_{CW}(U) : [k] \mapsto \left\{ \itexarray{ \Omega^\bullet(U \times \Delta^k)_{vert} &\stackrel{A_{vert}}{\leftarrow}& CE(\mathfrak{g}) \\ \uparrow && \uparrow \\ \Omega^\bullet(U \times \Delta^k) &\stackrel{A}{\leftarrow}& W(\mathfrak{g}) \\ \uparrow && \uparrow \\ \Omega^\bullet(U) &\stackrel{\langle F_A\rangle}{\leftarrow}& inv(\mathfrak{g}) } \right\} \,. \end{displaymath} \end{defn} \begin{remark} \label{}\hypertarget{}{} If we just consider the top horizontal morphism in this diagram we obtain the object \begin{displaymath} \exp(\mathfrak{g})(U) : [k] \mapsto \left\{ \itexarray{ \Omega^\bullet(U \times \Delta^k)_{vert} &\stackrel{A_{vert}}{\leftarrow}& CE(\mathfrak{g}) } \right\} \end{displaymath} discussed in detail at [[Lie integration]]. If we consider the top square of the diagram we obtain the object \begin{displaymath} \exp(\mathfrak{g})_{diff}(U) : [k] \mapsto \left\{ \itexarray{ \Omega^\bullet(U \times \Delta^k)_{vert} &\stackrel{A_{vert}}{\leftarrow}& CE(\mathfrak{g}) \\ \uparrow && \uparrow \\ \Omega^\bullet(U \times \Delta^k) &\stackrel{A}{\leftarrow}& W(\mathfrak{g}) } \right\} \,. \end{displaymath} This forms a [[resolution]] of $\exp(\mathfrak{g})$ and may be thought of as the $\infty$-groupoid of [[pseudo-connection]]s. We have an evident sequence of morphisms \begin{displaymath} \itexarray{ \exp(\mathfrak{g})_{conn} &&& genuine\;connections \\ \downarrow \\ \exp(\mathfrak{g})_{CW} &&& pseudo-connection\;with\;global\;curvature\;characteristics \\ \downarrow \\ \exp(\mathfrak{g})_{diff} &&& pseudo-connections \\ \downarrow^{\mathrlap{\simeq}} \\ \exp(\mathfrak{g}) &&& bare bundles } \,, \end{displaymath} where we label the objects by the structures they classify, as discussed at [[∞-Chern-Weil theory]]. Here the botton morphism is a weak equivalence and the others are [[monomorphism]]s. Notice that in full [[∞-Chern-Weil theory]] the fundamental object of interest is really $\exp(\mathfrak{g})_{diff}$ -- the object of [[pseudo-connection]]s. The other objects only serve the purpose of picking particularly nice representatives: the object $\exp(\mathfrak{g})_{CW}$ may contain pseudo-connections, those for which at least the associated [[circle n-bundles with connection]] given by the $\infty$-Chern Weil homomorphism are genuine connections. This distinction is important: over objects $X \in$ [[?LieGrpd]] that are not [[smooth manifold]]s but for instance [[orbifold]]s, the genuine connections for higher Lie algebras do \emph{not} exhaust all nonabelian differential cocycles. This just means that not every differential class in this case does have a nice representative in the usual sense. \end{remark} \hypertarget{InfGaugeTrafo}{}\subsubsection*{{1-Morphisms: integration of infinitesimal gauge transformations}}\label{InfGaugeTrafo} The 1-[[morphism]]s in $\exp(\mathfrak{g})(U)$ may be thought of as [[gauge transformation]]s between $\mathfrak{g}$-valued forms. We unwind what these look like concretely. \begin{defn} \label{}\hypertarget{}{} Given a 1-morphism in $\exp(\mathfrak{g})(X)$, represented by $\mathfrak{g}$-valued forms \begin{displaymath} \Omega^\bullet(U \times \Delta^1) \leftarrow W(\mathfrak{g}) : A \end{displaymath} consider the unique decomposition \begin{displaymath} A = A_U + ( A_{vert} := \lambda \wedge d t) \; \; \,, \end{displaymath} with $A_U$ the horizonal differential form component and $t : \Delta^1 = [0,1] \to \mathbb{R}$ the canonical coordinate. We call $\lambda$ the \textbf{gauge parameter} . This is a function on $\Delta^1$ with values in 0-forms on $U$ for $\mathfrak{g}$ an ordinary [[Lie algebra]], plus 1-forms on $U$ for $\mathfrak{g}$ a [[Lie 2-algebra]], plus 2-forms for a Lie 3-algebra, and so forth. \end{defn} We describe now how this enccodes a gauge transformation \begin{displaymath} A_0(s=1) \stackrel{\lambda}{\to} A_U(s = 1) \,. \end{displaymath} \begin{remark} \label{}\hypertarget{}{} By the nature of the [[Weil algebra]] we have \begin{displaymath} \frac{d}{d s} A_U = d_U \lambda + [\lambda \wedge A] + [\lambda \wedge A \wedge A] + \cdots + \iota_s F_A \,, \end{displaymath} where the sum is over all higher brackets of the [[∞-Lie algebra]] $\mathfrak{g}$. \end{remark} \begin{remark} \label{}\hypertarget{}{} In [[Cartan calculus]] for $\mathfrak{g}$ an ordinary Lie algebra may write (see \href{Ehresmann+connection#FormulationInTermsOfCurvatureForm}{here}) the corresponding [[Ehresmann connection|second Ehresmann condition]] $\iota_{\partial_s} F_A = 0$ equivalently \begin{displaymath} \mathcal{L}_{\partial_s} A = ad_\lambda A \,. \end{displaymath} \end{remark} \begin{defn} \label{}\hypertarget{}{} Define the \textbf{[[covariant derivative]] of the gauge parameter} to be \begin{displaymath} \nabla \lambda := d \lambda + [A \wedge \lambda] + [A \wedge A \wedge \lambda] + \cdots \,. \end{displaymath} \end{defn} In this notation we have \begin{itemize}% \item the general identity \begin{equation} \frac{d}{d s} A_U = \nabla \lambda + (F_A)_s \label{ShiftedGaugeTrafo}\end{equation} \item the \textbf{horizontality} or \textbf{[[Ehresmann connection|second Ehresmann condition]]} (or ``strict \href{D%27Auria-Fre+formulation+of+supergravity#Rheonomy}{rheonomy}'') $\iota_{\partial_s} F_A = 0$, the [[differential equation]] \begin{equation} \frac{d}{d s} A_U = \nabla \lambda \,. \label{GaugeTrafo}\end{equation} \end{itemize} This is known as the equation for \textbf{infinitesimal [[gauge transformation]]s} of an $\infty$-Lie algebra valued form. \begin{remark} \label{}\hypertarget{}{} By [[Lie integration]] we have that $A_{vert}$ -- and hence $\lambda$ -- defines an element $\exp(\lambda)$ in the [[∞-Lie group]] that integrates $\mathfrak{g}$. The unique solution $A_U(s = 1)$ of the above [[differential equation]] at $s = 1$ for the initial values $A_U(s = 0)$ we may think of as the result of acting on $A_U(0)$ with the [[gauge transformation]] $\exp(\lambda)$. \end{remark} \hypertarget{examples}{}\subsection*{{Examples}}\label{examples} \hypertarget{lie_algebra_valued_1forms}{}\subsubsection*{{Lie algebra valued 1-forms}}\label{lie_algebra_valued_1forms} \begin{prop} \label{}\hypertarget{}{} \textbf{(connections on ordinary bundles)} For $\mathfrak{g}$ an ordinary [[Lie algebra]] with simply connected [[Lie group]] $G$ and for $\mathbf{B}G_{conn}$ the [[groupoid of Lie algebra-valued forms]] we have an [[isomorphism]] \begin{displaymath} \tau_1 \exp(\mathfrak{g})_{conn} = \mathbf{B}G_{conn} \end{displaymath} \end{prop} \begin{proof} To see this, first note that the sheaves of objects on both sides are manifestly isomorphic, both are the sheaf of $\Omega^1(-,\mathfrak{g})$. For morphisms, observe that for a form $\Omega^\bullet(U \times \Delta^1) \leftarow W(\mathfrak{g}) : A$ which we may decompose into a horizontal and a verical pice as $A = A_U + \lamnda \wedge d t$ the condition $\iota_{\partial_t} F_A = 0$ is equivalent to the [[differential equation]] \begin{displaymath} \frac{\partial}{\partial t} A = d_U \lambda + [\lambda, A] \,. \end{displaymath} For any initial value $A(0)$ this has the unique solution \begin{displaymath} A(t) = g(t)^{-1} (A + d_{U}) g(t) \,, \end{displaymath} where $g : [0,1] \to G$ is the [[parallel transport]] of $\lambda$: \begin{displaymath} \begin{aligned} & \frac{\partial}{\partial t} \left( g_(t)^{-1} (A + d_{U}) g(t) \right) \\ = & g(t)^{-1} (A + d_{U}) \lambda g(t) - g(t)^{-1} \lambda (A + d_{U}) g(t) \end{aligned} \end{displaymath} (where for ease of notaton we write actions as if $G$ were a [[matrix Lie group]]). In particular this implies that the endpoints of the path of $\mathfrak{g}$-valued 1-forms are related by the usual cocycle condition in $\mathbf{B}G_{conn}$ \begin{displaymath} A(1) = g(1)^{-1} (A + d_U) g(1) \,. \end{displaymath} In the same fashion one sees that given 2-cell in $\exp(\mathfrak{g})(U)$ and any 1-form on $U$ at one vertex, there is a unique lift to a 2-cell in $\exp(\mathfrak{g})_{conn}$, obtained by parallel transporting the form around. The claim then follows from the previous statement of [[Lie integration]] that $\tau_1 \exp(\mathfrak{g}) = \mathbf{B}G$. \end{proof} \hypertarget{lie_2algebra_valued_forms}{}\subsubsection*{{Lie 2-algebra valued forms}}\label{lie_2algebra_valued_forms} \begin{itemize}% \item For $\mathfrak{g}$ [[Lie 2-algebra]], a $\mathfrak{g}$-valued differential form in the sense described here is precisely an [[Lie 2-algebra valued form]]. \end{itemize} \hypertarget{ordinary_forms_and_the_de_rham_complex}{}\subsubsection*{{Ordinary $n$-forms and the de Rham complex}}\label{ordinary_forms_and_the_de_rham_complex} For $n \in \mathbb{N}$, $n \geq 1$ we have that $b^{n-1}\mathbb{R}$-valued differential forms are in natural bijection to ordinary closed [[differential form]]s in degree $n$ \begin{remark} \label{}\hypertarget{}{} Notice that under addition of differential forms, $\exp(b^{n-1}\mathbb{R})_{conn}$ is over each $U \in CartSp$ an abelian [[simplicial group]]. Under the [[Dold-Kan correspondence]] $Ch_\bullet^+ \stackrel{\overset{N}{\leftarrow}}{\underset{\Xi}{\to}} sAb$ we may therefore identify $\exp(b^{n-1}\mathbb{R})_{conn}$ with a presheaf $N \exp(b^{n-1}\mathbb{R})_{conn}$ of chain complexes. \end{remark} \begin{prop} \label{}\hypertarget{}{} The degreewise [[fiber integration]] of differential forms over simplices constitutes a morphism \begin{displaymath} \int_{\Delta^\bullet} : N\exp(b^{n-1}\mathbb{R})_{conn} \to \left( C^\infty(-, \mathbb{R}) \stackrel{d_{dR}}{\to} \Omega^1(-) \stackrel{d_{dR}}{\to} \cdots \stackrel{d_{dR}}{\to} \Omega^n(-) \right) \,. \end{displaymath} that is a weak equivalence. \end{prop} This is shown at based on the discussion at . \hypertarget{supergravity_fields}{}\subsubsection*{{Supergravity fields}}\label{supergravity_fields} What is called an ``extended soft group manifold'' in the literature on the [[D'Auria-Fre formulation of supergravity]] is really precisely a collection of $\infty$-Lie algebroid valued forms with values in a super $\infty$-Lie algebra such as the [[supergravity Lie 3-algebra]] (for 11-dimensional [[supergravity]]). The way [[curvature]] and [[Bianchi identity]] are read off from ``extded soft group manifolds'' in this literature is -- apart from this difference in terminology -- precisely what is described above. \hypertarget{related_concepts}{}\subsection*{{Related concepts}}\label{related_concepts} \begin{itemize}% \item [[groupoid of Lie-algebra valued forms]] \item [[2-groupoid of Lie 2-algebra valued forms]] \item [[3-groupoid of Lie 3-algebra valued forms]] \item \textbf{$\infty$-groupoid of ∞-Lie-algebra valued forms} \end{itemize} \hypertarget{references}{}\subsection*{{References}}\label{references} The (obvious but conceptually important) observation that [[Lie algebra-valued 1-forms]] regarded as morphisms of [[graded vector space]]s $\Omega^\bullet(X) \leftarrow \wedge^1 \mathfrak{g}^* : A$ are equivalently morphisms of dg-algebras out of the [[Weil algebra]] $\Omega^\bullet(X) \leftarrow W(\mathfrak{g}) : A$ and that one may think of as the identity $W(\mathfrak{g}) \leftarrow W(\mathfrak{g}) : Id$ as the \emph{universal $\mathfrak{g}$-connection} appears in early articles for instance highlighted on p. 15 of \begin{itemize}% \item Franz W. Kamber; Philippe Tondeur, \emph{Semisimplicial Weil algebras and characteristic classes for foliated bundles in ech cohomology} , Differential geometry (Proc. Sympos. Pure Math., Vol. XXVII, Stanford Univ., Stanford, Calif., 1973), Part 1, pp. 283--294. Amer. Math. Soc., Providence, R.I., (1975). \end{itemize} following [[Eli Cartan]]`s influential work (see [[Weil algebra]] for more references). The (evident) generalization to Weil algebras of [[∞-Lie algebra]]s and [[∞-Lie algebroid]]s is considered explicitly in \begin{itemize}% \item Hisham Sati, Urs Schreiber, Jim Staasheff, \emph{$L_\infty$-algebra valued connections} () \end{itemize} but -- somewhat implicitly -- this construction appears earlier, notably in the [[D'Auria-Fre formulation of supergravity]]. A collection of such precursors to these notions is collected at \begin{itemize}% \item [[schreiber:differential cohomology in an (∞,1)-topos -- references]]: \end{itemize} The structure of the formula \eqref{GaugeTrafo} for infinitesimal gauge transformations of higher forms is widely known in the literature on [[supergravity]] and [[string theory]], if maybe not formalized in terms of $\infty$-Lie algebra theory as we do here. One exception is the remarkable book \begin{itemize}% \item [[Leonardo Castellani]], [[Riccardo D'Auria]], [[Pietro Fre]], \emph{[[Supergravity and Superstrings - A Geometric Perspective]]} . \end{itemize} In this old book no $\infty$-Lie algebras are mentioned explicitly, but the [[dg-algebra]] computations that are considered are easily seen to be precisely their [[Chevalley-Eilenberg algebra]]-incarnations. The authors use the term \emph{extended [[soft group manifold]]} for what here we identify as an $\infty$-Lie algebra valued form $T X \to inn(\mathfrak{g})$. With this terminological translation understood, and observing that all their constructions straightforwardly generalize to more general dg-algebras than these authors conisder explicitly, we find that \begin{itemize}% \item our equation \eqref{ShiftedGaugeTrafo} for the possibly shifted gauge transformation is their equation I.3.136; \item our equation \eqref{GaugeTrafo} for the genuine gauge transfomation is their equation for \emph{horizontal} or [[rheonomy|rheonomic]] gauge transformations III.3.23 . \end{itemize} In fact their full rheonomy constraint III.3.32 is essentialy the same horizontality constraint, but applied not just to the 1-simplex $\Delta^1$, but to the [[supermanifold|super simplex]] $\Delta^{1|p}$. 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