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We first extend Cheeger-Colding Almost Splitting Theorem to smooth metric measure spaces. Arguments utilizing this extension of the Almost Splitting Theorem show that if a smooth metric measure space has almost nonnegative Bakry-Emery Ricci…

Differential Geometry · Mathematics 2013-11-06 Maree Jaramillo

We extend the classical Mercer theorem to reproducing kernel Hilbert spaces whose elements are functions from a measurable space $X$into $\mathbb C^n$. Given a finite measure $\mu$ on $X$, we represent the reproducing kernel $K$ as…

Functional Analysis · Mathematics 2011-10-19 Ernesto De Vito , Veronica Umanita` , Silvia Villa

Understanding how singularities behave under small perturbations is a central theme in singularity theory. In this paper we establish sufficient conditions for families of analytic function-germs on a germ of a complex analytic space to…

Algebraic Geometry · Mathematics 2025-12-04 R. Giménez Conejero , Andreas Lind , Aurélio Menegon

We generalize some of the results in [arXiv: math.CV/0503430], and prove a bump-lemma for closed sets in semi 1-coronae. From this we obtain some finite cohomology results and an extension theorem for analytic subsets in 1-coronae.

Complex Variables · Mathematics 2007-05-23 Alberto Saracco , Giuseppe Tomassini

We give results on reduced complex-analytic curve germs which relate their indecomposable maximal Cohen-Macaulay (MCM) modules to their lattice homology groups and related invariants, thereby providing a connection between the algebraic…

Algebraic Geometry · Mathematics 2025-10-16 Alex Hof , András Némethi

Using results from theory of operators on a Hilbert space, we prove approximation results for matrix-valued holomorphic functions on the unit disc and the unit bidisc. The essential tools are the theory of unitary dilation of a contraction…

Complex Variables · Mathematics 2023-06-27 Daniel Alpay , Tirthankar Bhattacharyya , Abhay Jindal , Poornendu Kumar

We characterize the model spaces $K_\Theta$ in which functions with smooth boundary extensions are dense. It is shown that such approximations are possible if and only if the singular measure associated to the singular inner factor of…

Functional Analysis · Mathematics 2021-06-18 Adem Limani , Bartosz Malman

We construct a special family of equivariant coherent sheaves on the Hilbert scheme on $n$-points in the affine plane. The equivariant Euler characteristic of these sheaves are closely related to the symmetic functions $(-1)^{n-1} \nabla…

Algebraic Geometry · Mathematics 2018-08-17 Soumya Dipta Banerjee , Mahir Bilen Can , Adriano Garsia

To a multi-index filtration (say, on the ring of germs of functions on a germ of a complex analytic variety) one associates several invariants: the Hilbert function, the Poincar\'e series, the generalized Poincar\'e series, and the…

Algebraic Geometry · Mathematics 2013-03-18 A. Campillo , F. Delgado , S. M. Gusein-Zade

We use discrete holomorphic polynomials to prove that, given a refining sequence of critical maps of a Riemann surface, any holomorphic function can be approximated by a converging sequence of discrete holomorphic functions.

Mathematical Physics · Physics 2007-05-23 Christian Mercat

By Hironaka Desingularization Theorem, any real analytic function has only normal crossing singularities after a suitable modification. We focus on the analytic equivalence of such functions with only normal crossing singularities. We prove…

Algebraic Geometry · Mathematics 2014-02-26 Goulwen Fichou , Masahiro Shiota

This note shows that split-2 bisimulation equivalence (also known as timed equivalence) affords a finite equational axiomatization over the process algebra obtained by adding an auxiliary operation proposed by Hennessy in 1981 to the…

Logic in Computer Science · Computer Science 2017-01-11 Luca Aceto , Wan Fokkink , Anna Ingolfsdottir , Bas Luttik

In classical model theory, the Keisler--Shelah theorem establishes a fundamental connection between the elementary equivalence of structures and the isomorphism of their ultrapowers. Motivated by this, one may ask whether an analogous…

Operator Algebras · Mathematics 2026-05-14 Akihiko Arai

We show that for a noetherian algebra $A$ whose bounded dg derived category is smooth, the singular Hochschild cohomology (=Tate--Hochschild cohomology) is isomorphic, as a graded algebra, to the Hochschild cohomology of the dg singularity…

Representation Theory · Mathematics 2020-09-10 Bernhard Keller

Let $\Delta$ be a simplicial complex. We study the expansions of $\Delta$ mainly to see how the algebraic and combinatorial properties of $\Delta$ and its expansions are related to each other. It is shown that $\Delta$ is Cohen-Macaulay,…

Commutative Algebra · Mathematics 2017-01-18 Rahim Rahmati-Asghar , Somayeh Moradi

We approximate functions defined on smooth bounded domains by elements of the eigenspaces of the Laplacian or the Stokes operator in such a way that the approximations are bounded and converge in both Sobolev and Lebesgue spaces. We prove…

Functional Analysis · Mathematics 2021-08-05 Charles L. Fefferman , Karol W. Hajduk , James C. Robinson

We give a canonical construction of a balanced big Cohen-Macaulay algebra for a domain of finite type over $\mathbb C$ by taking ultraproducts of absolute integral closures in positive characteristic. This yields a new tight closure…

Commutative Algebra · Mathematics 2007-05-23 Hans Schoutens

Consider a local chain Differential Graded algebra, such as the singular chain complex of a pathwise connected topological group. In two previous papers, a number of homological results were proved for such an algebra: An Amplitude…

Rings and Algebras · Mathematics 2008-01-11 Anders J. Frankild , Peter Jorgensen

We prove the following result due to Hamidoune using an analytic approach. Suppose that A is a subset of a finite group G with |AA^{-1}| \leq (2-\varepsilon)|A|. Then there is a subgroup H of G and a set X of size O_\varepsilon(1) such that…

Classical Analysis and ODEs · Mathematics 2012-12-04 Tom Sanders

Let F be a holomorphic map whose components satisfy some polynomial relations. We present an algorithm for constructing Nash maps locally approximating F, whose components satisfy the same relations.

Complex Variables · Mathematics 2020-10-05 Marcin Bilski , Peter Scheiblechner