| nr |
titel |
auteur |
tijdschrift |
jaar |
jaarg. |
afl. |
pagina('s) |
type |
| 1 |
A Blichfeldt-type inequality for centrally symmetric convex bodies
|
Henze, Matthias
|
|
2012
|
|
3-4 |
p. 371-379
|
artikel
|
| 2 |
Absorbing sets of homogeneous subtractive algorithms
|
Miernowski, Tomasz
|
|
2012
|
|
3-4 |
p. 547-569
|
artikel
|
| 3 |
A complex of incompressible surfaces for handlebodies and the mapping class group
|
Charitos, Charalampos
|
|
2012
|
|
3-4 |
p. 405-415
|
artikel
|
| 4 |
A construction of integer-valued polynomials with prescribed sets of lengths of factorizations
|
Frisch, Sophie
|
|
2013
|
|
3-4 |
p. 341-350
|
artikel
|
| 5 |
A 2-local characterization of M(24)′
|
Salarian, M. Reza
|
|
2011
|
|
3-4 |
p. 583-588
|
artikel
|
| 6 |
A logarithmically improved regularity criterion for the Navier–Stokes equations
|
Liu, Qiao
|
|
2011
|
|
3-4 |
p. 503-509
|
artikel
|
| 7 |
A minimum problem with two-phase free boundary in Orlicz spaces
|
Zheng, Jun
|
|
2013
|
|
3-4 |
p. 441-475
|
artikel
|
| 8 |
An algebraic approach to manifold-valued generalized functions
|
Burtscher, Annegret
|
|
2011
|
|
3-4 |
p. 361-370
|
artikel
|
| 9 |
A note on Poisson brackets for orthogonal polynomials on the unit circle
|
Nenciu, Irina
|
|
2012
|
|
3-4 |
p. 425-436
|
artikel
|
| 10 |
A note on the Bahadur representation of sample quantiles for α-mixing random variables
|
Xing, Guo-dong
|
|
2011
|
|
3-4 |
p. 579-596
|
artikel
|
| 11 |
A note on the uniqueness of the canonical connection of a naturally reductive space
|
Olmos, Carlos
|
|
2013
|
|
3-4 |
p. 379-386
|
artikel
|
| 12 |
An upper bound for the power pseudovariety PCS
|
Kad’ourek, Jiří
|
|
2011
|
|
3-4 |
p. 411-440
|
artikel
|
| 13 |
Arbitrarily small weak solutions for a nonlinear eigenvalue problem in Orlicz–Sobolev spaces
|
Bonanno, Gabriele
|
|
2011
|
|
3-4 |
p. 305-318
|
artikel
|
| 14 |
A simple proof of Schmidt–Summerer’s inequality
|
German, Oleg N.
|
|
2012
|
|
3-4 |
p. 361-370
|
artikel
|
| 15 |
A sufficient condition for the non-finite basis property of semigroups
|
Lee, Edmond W. H.
|
|
2011
|
|
3-4 |
p. 461-472
|
artikel
|
| 16 |
A ternary additive problem
|
Hoffman, John W.
|
|
2013
|
|
3-4 |
p. 293-321
|
artikel
|
| 17 |
Book reviews
|
|
|
2012
|
|
3-4 |
p. 597-604
|
artikel
|
| 18 |
Book reviews
|
|
|
2012
|
|
3-4 |
p. 601-604
|
artikel
|
| 19 |
Book reviews
|
|
|
2013
|
|
3-4 |
p. 487-489
|
artikel
|
| 20 |
Book reviews
|
Auinger, Karl
|
|
2012
|
|
3-4 |
p. 601-610
|
artikel
|
| 21 |
Book reviews
|
|
|
2013
|
|
3-4 |
p. 499-502
|
artikel
|
| 22 |
Boundary of central tiles associated with Pisot beta-numeration and purely periodic expansions
|
Akiyama, Shigeki
|
|
2008
|
|
3-4 |
p. 377-419
|
artikel
|
| 23 |
Calderón–Zygmund operators in the Bessel setting
|
Betancor, Jorge J.
|
|
2011
|
|
3-4 |
p. 375-403
|
artikel
|
| 24 |
Central limit theorems for hyperbolic spaces and Jacobi processes on $$[0,\infty [$$
|
Voit, Michael
|
|
2012
|
|
3-4 |
p. 441-468
|
artikel
|
| 25 |
Characterizations of the simple group $${^2D_n(3)}$$ by prime graph and spectrum
|
Foroudi Ghasemabadi, Mahnaz
|
|
2011
|
|
3-4 |
p. 347-361
|
artikel
|
| 26 |
“Compactly” supported frames for spaces of distributions on the ball
|
Kyriazis, George
|
|
2011
|
|
3-4 |
p. 365-391
|
artikel
|
| 27 |
Compact open sets in dual spaces and projections in group algebras of [FC]− groups
|
Kaniuth, Eberhard
|
|
2010
|
|
3-4 |
p. 335-352
|
artikel
|
| 28 |
Concentration of points on curves in finite fields
|
Cilleruelo, Javier
|
|
2013
|
|
3-4 |
p. 315-327
|
artikel
|
| 29 |
Constructions of Pisot and Salem numbers with flat palindromes
|
Akiyama, Shigeki
|
|
2008
|
|
3-4 |
p. 265-275
|
artikel
|
| 30 |
Crystallographic number systems
|
Loridant, Benoît
|
|
2011
|
|
3-4 |
p. 511-529
|
artikel
|
| 31 |
Cubic Pisot unit combinatorial games
|
Duchêne, Eric
|
|
2008
|
|
3-4 |
p. 217-249
|
artikel
|
| 32 |
Decomposition of conditionally positive definite functions on commutative hypergroups
|
Berschneider, Georg
|
|
2011
|
|
3-4 |
p. 329-340
|
artikel
|
| 33 |
Dedekind sums in function fields
|
Hamahata, Yoshinori
|
|
2012
|
|
3-4 |
p. 461-480
|
artikel
|
| 34 |
Derivations and linear functions along rational functions
|
Gselmann, Eszter
|
|
2012
|
|
3-4 |
p. 355-370
|
artikel
|
| 35 |
Divergence points and normal numbers
|
Bisbas, Antonis
|
|
2011
|
|
3-4 |
p. 341-356
|
artikel
|
| 36 |
Equidistribution of expanding measures with local maximal dimension and diophantine approximation
|
Shi, Ronggang
|
|
2011
|
|
3-4 |
p. 513-541
|
artikel
|
| 37 |
Error bounds for quasi-Monte Carlo integration for $${\fancyscript{L}_{\infty}}$$ with uniform point sets
|
Hu, Su
|
|
2011
|
|
3-4 |
p. 327-334
|
artikel
|
| 38 |
Euler, Pisot, Prouhet–Thue–Morse, Wallis and the duplication of sines
|
Allouche, J.-P.
|
|
2008
|
|
3-4 |
p. 301-315
|
artikel
|
| 39 |
Exhaustive search methods for CNS polynomials
|
Burcsi, Péter
|
|
2008
|
|
3-4 |
p. 421-430
|
artikel
|
| 40 |
Factors of some lacunary $$q$$q-binomial sums
|
Pan, Hao
|
|
2013
|
|
3-4 |
p. 387-398
|
artikel
|
| 41 |
Feebly compact paratopological groups and real-valued functions
|
Sanchis, Manuel
|
|
2012
|
|
3-4 |
p. 579-597
|
artikel
|
| 42 |
Finite groups all of whose second maximal subgroups are $${\mathcal{H }}_p$$-groups
|
Zhong, Xianggui
|
|
2013
|
|
3-4 |
p. 477-486
|
artikel
|
| 43 |
Finite groups with non-nilpotent maximal subgroups
|
Lu, Jiakuan
|
|
2012
|
|
3-4 |
p. 425-431
|
artikel
|
| 44 |
Fourier analysis of subgroup conjugacy invariant functions on finite groups
|
Scarabotti, Fabio
|
|
2012
|
|
3-4 |
p. 465-479
|
artikel
|
| 45 |
Fourier transforms on an amalgam type space
|
Liflyand, E.
|
|
2013
|
|
3-4 |
p. 345-355
|
artikel
|
| 46 |
Free lattice-ordered groups and the space of left orderings
|
Clay, Adam
|
|
2011
|
|
3-4 |
p. 417-430
|
artikel
|
| 47 |
Frequencies of digits under trigonometric perturbations
|
Barreira, Luis
|
|
2012
|
|
3-4 |
p. 357-374
|
artikel
|
| 48 |
Frequently hypercyclic subspaces
|
Bonilla, A.
|
|
2012
|
|
3-4 |
p. 305-320
|
artikel
|
| 49 |
Generalized Lie-Bäcklund theorem for Lie class $$\omega =1$$ω=1 overdetermined systems
|
Kruglikov, Boris
|
|
2013
|
|
3-4 |
p. 395-414
|
artikel
|
| 50 |
Geometry of the common dynamics of flipped Pisot substitutions
|
Sing, B.
|
|
2008
|
|
3-4 |
p. 431-448
|
artikel
|
| 51 |
Global injectivity conditions for planar maps
|
Pintea, Cornel
|
|
2013
|
|
3-4 |
p. 399-413
|
artikel
|
| 52 |
Global symplectic coordinates on gradient Kähler–Ricci solitons
|
Loi, Andrea
|
|
2012
|
|
3-4 |
p. 415-423
|
artikel
|
| 53 |
Global weak solutions for a periodic two-component μ-Hunter–Saxton system
|
Liu, Jingjing
|
|
2011
|
|
3-4 |
p. 503-521
|
artikel
|
| 54 |
Graphs, partitions and classes of groups
|
Ballester-Bolinches, Adolfo
|
|
2010
|
|
3-4 |
p. 309-318
|
artikel
|
| 55 |
Harmonic functions on [IN] and central hypergroups
|
Amini, Massoud
|
|
2012
|
|
3-4 |
p. 267-284
|
artikel
|
| 56 |
Harmonic mappings in Bergman spaces
|
Chen, Sh.
|
|
2012
|
|
3-4 |
p. 325-342
|
artikel
|
| 57 |
Hausdorff dimension of the recurrence set of Gauss transformation
|
Wang, Sikui
|
|
2011
|
|
3-4 |
p. 579-590
|
artikel
|
| 58 |
Homomorphisms with respect to a function
|
Boulabiar, Karim
|
|
2011
|
|
3-4 |
p. 357-360
|
artikel
|
| 59 |
How large are the level sets of the Takagi function?
|
Allaart, Pieter C.
|
|
2012
|
|
3-4 |
p. 311-331
|
artikel
|
| 60 |
Identities with Engel conditions on derivations
|
Koşan, M. Tamer
|
|
2010
|
|
3-4 |
p. 543-556
|
artikel
|
| 61 |
Isoperimetric inequalities for submanifolds with bounded mean curvature
|
Seo, Keomkyo
|
|
2011
|
|
3-4 |
p. 525-542
|
artikel
|
| 62 |
Journées de Numération, Graz University of Technology, April 16–20, 2007
|
Arnoux, Pierre
|
|
2008
|
|
3-4 |
p. 213-215
|
artikel
|
| 63 |
Lagrangian submanifolds and the Hamilton–Jacobi equation
|
Barbero-Liñán, María
|
|
2013
|
|
3-4 |
p. 269-290
|
artikel
|
| 64 |
Lagrangian submanifolds in k-symplectic settings
|
León, M. de
|
|
2012
|
|
3-4 |
p. 381-404
|
artikel
|
| 65 |
Limit distributions in metric discrepancy theory
|
Aistleitner, Christoph
|
|
2012
|
|
3-4 |
p. 253-265
|
artikel
|
| 66 |
Linear combinations of hypersurfaces in hyperbolic space
|
Gallego, E.
|
|
2012
|
|
3-4 |
p. 329-354
|
artikel
|
| 67 |
Local tensor valuations on convex polytopes
|
Schneider, Rolf
|
|
2012
|
|
3-4 |
p. 459-479
|
artikel
|
| 68 |
Local wave-front sets of Banach and Fréchet types, and pseudo-differential operators
|
Coriasco, Sandro
|
|
2012
|
|
3-4 |
p. 285-316
|
artikel
|
| 69 |
Manin’s conjecture for a quartic del Pezzo surface with A3 singularity and four lines
|
Le Boudec, Pierre
|
|
2011
|
|
3-4 |
p. 481-502
|
artikel
|
| 70 |
Matrix near-rings and 0-primitivity
|
Ke, W.-F.
|
|
2010
|
|
3-4 |
p. 353-363
|
artikel
|
| 71 |
Minoration of the complexity function associated to a translation on the torus
|
Bédaride, Nicolas
|
|
2013
|
|
3-4 |
p. 291-304
|
artikel
|
| 72 |
Morita invariants for semigroups with local units
|
Laan, Valdis
|
|
2011
|
|
3-4 |
p. 441-451
|
artikel
|
| 73 |
Multiplicity of solutions for differential inclusion problems in $${\mathbb{R}^N}$$ involving the p(x)-Laplacian
|
Ge, Bin
|
|
2011
|
|
3-4 |
p. 363-380
|
artikel
|
| 74 |
Mutually permutable products and conjugacy classes
|
Ballester-Bolinches, A.
|
|
2012
|
|
3-4 |
p. 305-310
|
artikel
|
| 75 |
New examples of Beauville surfaces
|
Barker, Nathan
|
|
2011
|
|
3-4 |
p. 319-327
|
artikel
|
| 76 |
New non-standard topologies
|
Khalfallah, Adel
|
|
2013
|
|
3-4 |
p. 323-344
|
artikel
|
| 77 |
Non-metric two-component Euler equations on the circle
|
Escher, Joachim
|
|
2011
|
|
3-4 |
p. 449-459
|
artikel
|
| 78 |
Normal extensions of subnormal linear relations via quaternionic Cayley transforms
|
Sandovici, Adrian
|
|
2012
|
|
3-4 |
p. 437-463
|
artikel
|
| 79 |
Normal families of meromorphic functions and shared values
|
Wu, Xiangzhong
|
|
2010
|
|
3-4 |
p. 569-578
|
artikel
|
| 80 |
On a class of sofic affine invariant subsets of the 2-torus related to an Erdős problem
|
Olivier, Eric
|
|
2011
|
|
3-4 |
p. 447-497
|
artikel
|
| 81 |
On additive decompositions of the set of primitive roots modulo p
|
Dartyge, Cécile
|
|
2011
|
|
3-4 |
p. 317-328
|
artikel
|
| 82 |
On a Diophantine inequality involving prime powers
|
Shi, Sanying
|
|
2012
|
|
3-4 |
p. 423-440
|
artikel
|
| 83 |
On an example of finite hybrid quasi-Monte Carlo point sets
|
Kritzer, Peter
|
|
2011
|
|
3-4 |
p. 443-459
|
artikel
|
| 84 |
On Borel almost disjoint families
|
Marciszewski, Witold
|
|
2012
|
|
3-4 |
p. 545-562
|
artikel
|
| 85 |
On finite simple groups acting on homology spheres
|
Guazzi, Alessandra
|
|
2012
|
|
3-4 |
p. 371-381
|
artikel
|
| 86 |
On higher moments of Fourier coefficients of holomorphic cusp forms II
|
Lü, Guangshi
|
|
2012
|
|
3-4 |
p. 409-422
|
artikel
|
| 87 |
On Huppert’s Conjecture for the Monster and Baby Monster
|
Tong-Viet, Hung P.
|
|
2011
|
|
3-4 |
p. 589-600
|
artikel
|
| 88 |
On Karatsuba’s problem concerning the divisor function
|
Korolev, M. A.
|
|
2011
|
|
3-4 |
p. 403-441
|
artikel
|
| 89 |
On linear combinations of units with bounded coefficients and double-base digit expansions
|
Krenn, Daniel
|
|
2012
|
|
3-4 |
p. 377-394
|
artikel
|
| 90 |
On minimal two-spheres immersed in complex Grassmann manifolds with parallel second fundamental form
|
Jiao, Xiaoxiang
|
|
2012
|
|
3-4 |
p. 381-401
|
artikel
|
| 91 |
On $$S$$-permutably embedded subgroups of finite groups
|
Ballester-Bolinches, A.
|
|
2013
|
|
3-4 |
p. 247-257
|
artikel
|
| 92 |
On the Bertini theorem in arbitrary characteristic
|
Jelonek, Zbigniew
|
|
2012
|
|
3-4 |
p. 351-355
|
artikel
|
| 93 |
On the completeness of a metric related to the Bergman metric
|
Dinew, Żywomir
|
|
2013
|
|
3-4 |
p. 277-291
|
artikel
|
| 94 |
On the dichotomy of Perron numbers and beta-conjugates
|
Verger-Gaugry, Jean-Louis
|
|
2008
|
|
3-4 |
p. 277-299
|
artikel
|
| 95 |
On the entropy of a family of random substitutions
|
Nilsson, Johan
|
|
2012
|
|
3-4 |
p. 563-577
|
artikel
|
| 96 |
On the equilibria of finely discretized curves and surfaces
|
Domokos, Gábor
|
|
2011
|
|
3-4 |
p. 321-345
|
artikel
|
| 97 |
On the Erdős–Falconer distance problem for two sets of different size in vector spaces over finite fields
|
Dietmann, Rainer
|
|
2012
|
|
3-4 |
p. 343-359
|
artikel
|
| 98 |
On the fast Khintchine spectrum in continued fractions
|
Fan, Aihua
|
|
2013
|
|
3-4 |
p. 329-340
|
artikel
|
| 99 |
On the geometry of linear Weingarten hypersurfaces in the hyperbolic space
|
Aquino, Cicero P.
|
|
2013
|
|
3-4 |
p. 259-268
|
artikel
|
| 100 |
On the Li coefficients for the Dirichlet $$L$$-functions
|
Mazhouda, Kamel
|
|
2012
|
|
3-4 |
p. 405-423
|
artikel
|
| 101 |
On the number of pairs of positive integers x, y ≤ H such that x2 + y2 + 1 is squarefree
|
Tolev, D. I.
|
|
2010
|
|
3-4 |
p. 557-567
|
artikel
|
| 102 |
On the number of summands in a random prime partition
|
Ralaivaosaona, Dimbinaina
|
|
2011
|
|
3-4 |
p. 505-524
|
artikel
|
| 103 |
On the point-stabiliser in a transitive permutation group
|
Potočnik, Primož
|
|
2011
|
|
3-4 |
p. 497-504
|
artikel
|
| 104 |
On the subalgebra of a Fourier–Stieltjes algebra generated by pure positive definite functions
|
Cheng, Yin-Hei
|
|
2013
|
|
3-4 |
p. 305-314
|
artikel
|
| 105 |
On traces of general decomposition spaces
|
Nielsen, Morten
|
|
2013
|
|
3-4 |
p. 443-457
|
artikel
|
| 106 |
On universality for linear combinations of L-functions
|
Nakamura, Takashi
|
|
2011
|
|
3-4 |
p. 433-446
|
artikel
|
| 107 |
Palindromes in linear recurrence sequences
|
Cilleruelo, Javier
|
|
2013
|
|
3-4 |
p. 433-442
|
artikel
|
| 108 |
Polarities and planar collineations of Moufang planes
|
Knarr, Norbert
|
|
2012
|
|
3-4 |
p. 383-395
|
artikel
|
| 109 |
Positional number systems with digits forming an arithmetic progression
|
Heuberger, Clemens
|
|
2008
|
|
3-4 |
p. 349-375
|
artikel
|
| 110 |
PP* estimates for the truncated Carleson operator
|
Prestini, Elena
|
|
2012
|
|
3-4 |
p. 571-581
|
artikel
|
| 111 |
Pseudo-Riemannian manifolds modelled on symmetric spaces
|
Dušek, Zdeněk
|
|
2010
|
|
3-4 |
p. 319-326
|
artikel
|
| 112 |
Rational preimages in families of dynamical systems
|
Levin, Aaron
|
|
2012
|
|
3-4 |
p. 473-501
|
artikel
|
| 113 |
Real hypersurfaces in complex two-plane Grassmannians with generalized Tanaka–Webster Reeb parallel shape operator
|
Jeong, Imsoon
|
|
2013
|
|
3-4 |
p. 357-376
|
artikel
|
| 114 |
Recurrence in β-expansion over formal Laurent series
|
Fan, Qibin
|
|
2011
|
|
3-4 |
p. 379-394
|
artikel
|
| 115 |
Self-similar structure on intersection of Cartesian product of Cantor triadic sets with their translations
|
Yao, Yuanyuan
|
|
2011
|
|
3-4 |
p. 591-600
|
artikel
|
| 116 |
Sequences with constant number of return words
|
Balková, L’ubomíra
|
|
2008
|
|
3-4 |
p. 251-263
|
artikel
|
| 117 |
Shadowing, entropy and minimal subsystems
|
Moothathu, T. K. Subrahmonian
|
|
2013
|
|
3-4 |
p. 357-378
|
artikel
|
| 118 |
Simple exceptional groups of Lie type are determined by their character degrees
|
Tong-Viet, Hung P.
|
|
2011
|
|
3-4 |
p. 559-577
|
artikel
|
| 119 |
Some applications of the double large sieve
|
Baker, Roger
|
|
2012
|
|
3-4 |
p. 261-304
|
artikel
|
| 120 |
Some remarks on the asymptotic behavior of the semigroup associated with age-structured diffusive populations
|
Walker, Christoph
|
|
2012
|
|
3-4 |
p. 481-501
|
artikel
|
| 121 |
Space-filling curves and geodesic laminations. II: Symmetries
|
Sirvent, Víctor F.
|
|
2012
|
|
3-4 |
p. 543-558
|
artikel
|
| 122 |
Special biconformal changes of Kähler surface metrics
|
Derdzinski, Andrzej
|
|
2011
|
|
3-4 |
p. 431-448
|
artikel
|
| 123 |
Spectral self-affine measures with prime determinant
|
Li, Jian- Lin
|
|
2012
|
|
3-4 |
p. 397-407
|
artikel
|
| 124 |
Strong commutativity preserving generalized derivations on right ideals
|
Liu, Cheng-Kai
|
|
2011
|
|
3-4 |
p. 453-465
|
artikel
|
| 125 |
Sturmian substitutions on two letters, cutting paths and their projections
|
Rosema, S. W.
|
|
2008
|
|
3-4 |
p. 449-465
|
artikel
|
| 126 |
Successive radii and Minkowski addition
|
González, Bernardo
|
|
2010
|
|
3-4 |
p. 395-409
|
artikel
|
| 127 |
Superposition operators between weighted Banach spaces of analytic functions of controlled growth
|
Bonet, José
|
|
2012
|
|
3-4 |
p. 311-323
|
artikel
|
| 128 |
The approximate manifolds for the generalized (2+1)-dimensional long–short wave equations
|
Lu, Hong
|
|
2010
|
|
3-4 |
p. 393-411
|
artikel
|
| 129 |
The Banach algebras generated by representations of abelian semigroups
|
Mustafayev, H. S.
|
|
2011
|
|
3-4 |
p. 413-432
|
artikel
|
| 130 |
The first moment of Salié sums
|
Louvel, Benoît
|
|
2011
|
|
3-4 |
p. 523-543
|
artikel
|
| 131 |
The normality of digits in almost constant additive functions
|
Vandehey, J.
|
|
2012
|
|
3-4 |
p. 481-497
|
artikel
|
| 132 |
The Pompeiu problem and discrete groups
|
Puls, Michael J.
|
|
2013
|
|
3-4 |
p. 415-429
|
artikel
|
| 133 |
The sum of digits of primes in $${\mathbb{Z}}$$[i]
|
Drmota, Michael
|
|
2008
|
|
3-4 |
p. 317-347
|
artikel
|
| 134 |
The upper entropy index of a set and the Hausdorff dimension of its hyperspace
|
Das, Manav
|
|
2011
|
|
3-4 |
p. 371-378
|
artikel
|
| 135 |
Trace formulas for nuclear operators in spaces of Bochner integrable functions
|
Delgado, Julio
|
|
2013
|
|
3-4 |
p. 259-275
|
artikel
|
| 136 |
Transfers of metabelian p-groups
|
Mayer, Daniel C.
|
|
2010
|
|
3-4 |
p. 467-495
|
artikel
|
| 137 |
Twistor theory for CR quaternionic manifolds and related structures
|
Marchiafava, S.
|
|
2011
|
|
3-4 |
p. 531-545
|
artikel
|
| 138 |
Two incidence propositions in chain geometries
|
Özcan, Münevver
|
|
2011
|
|
3-4 |
p. 499-511
|
artikel
|
| 139 |
Ultrametric logarithm laws, II
|
Athreya, J. S.
|
|
2012
|
|
3-4 |
p. 333-356
|
artikel
|
| 140 |
Weak-strong uniqueness criterion for the $$\beta $$β-generalized surface quasi-geostrophic equation
|
Zhao, Jihong
|
|
2013
|
|
3-4 |
p. 431-440
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