00946nas a2200109 4500008004100000245009800041210006900139520046800208100001800676700001900694856012300713 2023 eng d00aA general splitting principle on RCD spaces and applications to spaces with positive spectrum0 ageneral splitting principle on RCD spaces and applications to sp3 a

In this paper we develop a general `analytic' splitting principle for RCD spaces: we show that if there is a function with suitable Laplacian and Hessian, then the space is (isomorphic to) a warped product. Our result covers most of the splitting-like results currently available in the literature about RCD spaces. We then apply it to extend to the non-smooth category some structural property of Riemannian manifolds obtained by Li and Wang.

1 aGigli, Nicola1 aMarconi, Fabio uhttps://www.math.sissa.it/publication/general-splitting-principle-rcd-spaces-and-applications-spaces-positive-spectrum01404nas a2200157 4500008004100000020001400041245008300055210006900138260001500207300001800222490000700240520091200247100001801159700002201177856004701199 2021 eng d a1559-002X00aA Differential Perspective on Gradient Flows on CAT(K)-Spaces and Applications0 aDifferential Perspective on Gradient Flows on CATKSpaces and App c2021/12/01 a11780 - 118180 v313 a

We review the theory of Gradient Flows in the framework of convex and lower semicontinuous functionals on $$\textsf {CAT} (\kappa )$$-spaces and prove that they can be characterized by the same differential inclusion $$y_t'\in -\partial ^-\textsf {E} (y_t)$$one uses in the smooth setting and more precisely that $$y_t'$$selects the element of minimal norm in $$-\partial ^-\textsf {E} (y_t)$$. This generalizes previous results in this direction where the energy was also assumed to be Lipschitz. We then apply such result to the Korevaar–Schoen energy functional on the space of $$L^2$$and CAT(0) valued maps: we define the Laplacian of such $$L^2$$map as the element of minimal norm in $$-\partial ^-\textsf {E} (u)$$, provided it is not empty. The theory of gradient flows ensures that the set of maps admitting a Laplacian is $$L^2$$-dense. Basic properties of this Laplacian are then studied.

1 aGigli, Nicola1 aNobili, Francesco uhttps://doi.org/10.1007/s12220-021-00701-500487nas a2200133 4500008004100000245008300041210006900124300001400193490001500207100002200222700001800244700002600262856006500288 2021 eng d00aDisplacement convexity of Entropy and the distance cost Optimal Transportation0 aDisplacement convexity of Entropy and the distance cost Optimal  a411–4270 vSer. 6, 301 aCavalletti, Fabio1 aGigli, Nicola1 aSantarcangelo, Flavia uhttps://afst.centre-mersenne.org/articles/10.5802/afst.1679/00414nas a2200097 4500008004100000245007200041210006900113100001800182700002200200856009400222 2021 eng d00aA first-order condition for the independence on p of weak gradients0 afirstorder condition for the independence on p of weak gradients1 aGigli, Nicola1 aNobili, Francesco uhttps://www.math.sissa.it/publication/first-order-condition-independence-p-weak-gradients10834nas a2200109 45000080041000002450068000412100065001095201041400174100001810588700002210606856009610628 2021 eng d00aMonotonicity formulas for harmonic functions in RCD(0,N) spaces0 aMonotonicity formulas for harmonic functions in RCD0N spaces3 a

We generalize to the RCD(0,N) setting a family of monotonicity formulas by Colding and Minicozzi for positive harmonic functions in Riemannian manifolds with non-negative Ricci curvature. Rigidity and almost rigidity statements are also proven, the second appearing to be new even in the smooth setting. Motivated by the recent work in [AFM] we also introduce the notion of electrostatic potential in RCD spaces, which also satisfies our monotonicity formulas. Our arguments are mainly based on new estimates for harmonic functions in RCD(K,N) spaces and on a new functional version of the `(almost) outer volume cone implies (almost) outer metric cone' theorem.

1 aGigli, Nicola1 aViolo, Ivan, Yuri uhttps://www.math.sissa.it/publication/monotonicity-formulas-harmonic-functions-rcd0n-spaces06995nas a2200121 4500008004100000245006500041210005800106520655200164100002106716700001806737700002406755856009406779 2021 eng d00aParallel transport on non-collapsed $\mathsfRCD(K,N)$ spaces0 aParallel transport on noncollapsed mathsfRCDKN spaces3 a

We provide a general theory for parallel transport on non-collapsed RCD spaces obtaining both existence and uniqueness results. Our theory covers the case of geodesics and, more generally, of curves obtained via the flow of sufficiently regular time dependent vector fields: the price that we pay for this generality is that we cannot study parallel transport along a single such curve, but only along almost all of these (in a sense related to the notions of Sobolev vector calculus and Regular Lagrangian Flow in the nonsmooth setting).
The class of ncRCD spaces contains finite dimensional Alexandrov spaces with curvature bounded from below, thus our construction provides a way of speaking about parallel transport in this latter setting alternative to the one proposed by Petrunin (1998). The precise relation between the two approaches is yet to be understood.

1 aCaputo, Emanuele1 aGigli, Nicola1 aPasqualetto, Enrico uhttps://www.math.sissa.it/publication/parallel-transport-non-collapsed-mathsfrcdkn-spaces01451nas a2200133 4500008004100000022001400041245008500055210007100140260000800211520101400219100001801233700001901251856004701270 2019 eng d a1432-206400aBenamou–Brenier and duality formulas for the entropic cost on RCD*(K,N) spaces0 aBenamou–Brenier and duality formulas for the entropic cost on RC cApr3 a

In this paper we prove that, within the framework of $\textsf{RCD}^\star(K,N)$ spaces with $N<\infty$, the entropic cost (i.e. the minimal value of the Schrödinger problem) admits:A threefold dynamical variational representation, in the spirit of the Benamou–Brenier formula for the Wasserstein distance; A Hamilton–Jacobi–Bellman dual representation, in line with Bobkov–Gentil–Ledoux and Otto–Villani results on the duality between Hamilton–Jacobi and continuity equation for optimal transport;A Kantorovich-type duality formula, where the Hopf–Lax semigroup is replaced by a suitable `entropic' counterpart.We thus provide a complete and unifying picture of the equivalent variational representations of the Schrödinger problem as well as a perfect parallelism with the analogous formulas for the Wasserstein distance. Riemannian manifolds with Ricci curvature bounded from below are a relevant class of $\textsf{RCD}^*(K,N)$ spaces and our results are new even in this setting.

1 aGigli, Nicola1 aTamanini, Luca uhttps://doi.org/10.1007/s00440-019-00909-100784nas a2200157 4500008004100000022001400041245006600055210006600121520024700187653002800434653002100462653003000483100001800513700002400531856007100555 2019 eng d a0723-086900aDifferential structure associated to axiomatic Sobolev spaces0 aDifferential structure associated to axiomatic Sobolev spaces3 a

The aim of this note is to explain in which sense an axiomatic Sobolev space over a general metric measure space (à la Gol’dshtein–Troyanov) induces – under suitable locality assumptions – a first-order differential structure.

10aAxiomatic Sobolev space10aCotangent module10aLocality of differentials1 aGigli, Nicola1 aPasqualetto, Enrico uhttp://www.sciencedirect.com/science/article/pii/S072308691830097500644nas a2200145 4500008004100000245006000041210005800101260003400159300001400193490000700207520015800214100001800372700001900390856008900409 2019 eng d00aA Note About the Strong Maximum Principle on RCD Spaces0 aNote About the Strong Maximum Principle on RCD Spaces bCanadian Mathematical Society a259–2660 v623 a

We give a direct proof of the strong maximum principle on finite dimensional RCD spaces based on the Laplacian comparison of the squared distance.

1 aGigli, Nicola1 aRigoni, Chiara uhttps://www.math.sissa.it/publication/note-about-strong-maximum-principle-rcd-spaces00394nas a2200109 4500008004100000245004900041210004800090100002000138700001800158700002400176856008400200 2019 eng d00aQuasi-continuous vector fields on RCD spaces0 aQuasicontinuous vector fields on RCD spaces1 aDebin, Clément1 aGigli, Nicola1 aPasqualetto, Enrico uhttps://www.math.sissa.it/publication/quasi-continuous-vector-fields-rcd-spaces00395nas a2200109 4500008004100000245004700041210004700088100001800135700002400153700002600177856008200203 2018 eng d00aDifferential of metric valued Sobolev maps0 aDifferential of metric valued Sobolev maps1 aGigli, Nicola1 aPasqualetto, Enrico1 aSoultanis, Elefterios uhttps://www.math.sissa.it/publication/differential-metric-valued-sobolev-maps00361nas a2200097 4500008004100000245005400041210004700095100001800142700002400160856007900184 2018 eng d00aOn the notion of parallel transport on RCD spaces0 anotion of parallel transport on RCD spaces1 aGigli, Nicola1 aPasqualetto, Enrico uhttps://www.math.sissa.it/publication/notion-parallel-transport-rcd-spaces00849nas a2200157 4500008004100000022001400041245009800055210006900153260000800222300000800230490000700238520036300245100001800608700001900626856004600645 2018 eng d a1432-083500aRecognizing the flat torus among RCD*(0,N) spaces via the study of the first cohomology group0 aRecognizing the flat torus among RCD0N spaces via the study of t cJun a1040 v573 a

We prove that if the dimension of the first cohomology group of a $\mathsf{RCD}^\star (0,N)$ space is $N$, then the space is a flat torus. This generalizes a classical result due to Bochner to the non-smooth setting and also provides a first example where the study of the cohomology groups in such synthetic framework leads to geometric consequences.

1 aGigli, Nicola1 aRigoni, Chiara uhttps://doi.org/10.1007/s00526-018-1377-z00433nas a2200121 4500008004100000245006100041210005800102300001400160490000700174100001800181700001900199856009300218 2018 eng d00aSecond order differentiation formula on RCD(K, N) spaces0 aSecond order differentiation formula on RCDK N spaces a377–3860 v291 aGigli, Nicola1 aTamanini, Luca uhttps://www.math.sissa.it/publication/second-order-differentiation-formula-rcdk-n-spaces00386nas a2200097 4500008004100000245006100041210005700102100001800159700001900177856009200196 2018 eng d00aSecond order differentiation formula on RCD*(K,N) spaces0 aSecond order differentiation formula on RCDKN spaces1 aGigli, Nicola1 aTamanini, Luca uhttps://www.math.sissa.it/publication/second-order-differentiation-formula-rcdkn-spaces00713nas a2200157 4500008004100000245004400041210004000085520026500125653001200390653001000402653004000412100002000452700002400472700001800496856004100514 2017 eng d00aThe injectivity radius of Lie manifolds0 ainjectivity radius of Lie manifolds3 a

We prove in a direct, geometric way that for any compatible Riemannian metric on a Lie manifold the injectivity radius is positive

10a(58J40)10a53C2110aMathematics - Differential Geometry1 aAntonini, Paolo1 aDe Philippis, Guido1 aGigli, Nicola uhttps://arxiv.org/pdf/1707.07595.pdf00410nas a2200097 4500008004100000245006900041210006500110100001800175700001900193856010000212 2017 eng d00aSecond order differentiation formula on compact RCD*(K,N) spaces0 aSecond order differentiation formula on compact RCDKN spaces1 aGigli, Nicola1 aTamanini, Luca uhttps://www.math.sissa.it/publication/second-order-differentiation-formula-compact-rcdkn-spaces00407nas a2200097 4500008004100000245006600041210006600107100001800173700002400191856009400215 2016 eng d00aBehaviour of the reference measure on RCD spaces under charts0 aBehaviour of the reference measure on RCD spaces under charts1 aGigli, Nicola1 aPasqualetto, Enrico uhttps://www.math.sissa.it/publication/behaviour-reference-measure-rcd-spaces-under-charts00471nas a2200097 4500008004100000245009600041210006900137100001800206700002400224856012500248 2016 eng d00aEquivalence of two different notions of tangent bundle on rectifiable metric measure spaces0 aEquivalence of two different notions of tangent bundle on rectif1 aGigli, Nicola1 aPasqualetto, Enrico uhttps://www.math.sissa.it/publication/equivalence-two-different-notions-tangent-bundle-rectifiable-metric-measure-spaces00744nas a2200097 4500008004100000245004800041210004300089520044800132100001800580856004800598 2013 en d00aThe splitting theorem in non-smooth context0 asplitting theorem in nonsmooth context3 aWe prove that an infinitesimally Hilbertian $CD(0,N)$ space containing a line splits as the product of $R$ and an infinitesimally Hilbertian $CD(0,N −1)$ space. By ‘infinitesimally Hilbertian’ we mean that the Sobolev space $W^{1,2}(X,d,m)$, which in general is a Banach space, is an Hilbert space. When coupled with a curvature-dimension bound, this condition is known to be stable with respect to measured Gromov-Hausdorff convergence.1 aGigli, Nicola uhttp://preprints.sissa.it/handle/1963/35306