# User talk:Yakovenko

Hi, welcome aboard of EoM.

I just checked and found 331 EoM pages with at least one of your favoured keywords: "singularities, limit cycles, normal forms, invariant manifolds, foliations"

If you want I could include here a list of links to those pages. --Ulf Rehmann 12:41, 15 April 2012 (CEST)

- Hi Ulf! Yes, please include these links.
- I will gradually learn the habits of the Wiki community. The first question is how to post answers/comments in the "Talk" pages: this one I do manually, but hopefully there should be some interface for such conversations (threaded or not).
- Thanks -- Sergei.

- Well, see below. It is probably not a good idea to let this spam your talk page so maybe you put it into a separate page. I have something similar on my user page, a bit pre-sorted by now, but was started with a list like the below.

- For editing, you can use your favoured editor, I have given hints on the help page, look for "It's all text".--Ulf Rehmann 15:29, 15 April 2012 (CEST)

- For the pages below, I have applied a program which inserts MR and ZBL numbers automatically. It does make mistakes, in particular sometimes it proposes too many entries, so please check. --Ulf Rehmann 19:01, 15 April 2012 (CEST)

331 files containing one of these keywords: "singularities|limit cycles|normal forms|invariant manifolds|foliation"

3-Sasakian manifold | Abelian differential | Abelian integral | Abel theorem | Abhyankar–Moh theorem | Acyclic group | Adaptive quadrature | Adjoint action | Adjunction theory | Alfvén waves | Algebraic function | Algebraic geometry | Algebraic surface | Algebraic topology | Algebraic variety | Algebra of logic | Algorithm, local | Analytic capacity | Analytic continuation | Analytic function | Analytic space | Analytic theory of differential equations | Approximation of functions | Arrangement of hyperplanes | Automatic control theory | Auto-oscillation | Average rotation | Baumslag-Solitar group | Bergman integral operator | Bernstein problem in differential geometry | Betti reciprocal theorem | Beurling-Lax theorem | Bézier spline | Bifurcation | Birational geometry | Birkhoff normal form | Birkhoff-Rott equation | Blow-up algebra | Bogolyubov theorem | Boolean function | Boolean functions, metric theory of | Boolean functions, minimization of | Boolean functions, normal forms of | Bordism | Borel transform | Boundary value problem, elliptic equations | Boundary value problem, numerical methods for partial differential equations | Braid theory | Branching of solutions | Branching point (of a minimal surface) | Buchsbaum ring | Canadian lynx series | Cancellation of singularities | Cassini oval | Caustic | C-convexity | Centre manifold | Centro-focus | Chasles-Cayley-Brill formula | Classifying space | Cluster set | Cobordism | Cobordism of knots | Codimension | Codimension-two bifurcations | Commutative algebra | Complete analytic function | Completely-integrable differential equation | Conjunctive normal form | Contact surgery | Continuity theorem | Control system | Cousin problems | Covering and packing | Critical point | Cyclic cohomology | Dead-end disjunctive normal form | Deformation | Degree of a mapping | Diffeomorphism | Difference scheme, variational | Differentiable manifold | Differential equation, ordinary | Differential equation, partial, complex-variable methods | Differential equation, partial, discontinuous initial (boundary) conditions | Differential equation, partial, free boundaries | Differential equation, partial, with singular coefficients | Differential games | Differential geometry of manifolds | Differential on a Riemann surface | Differential topology | Diffraction, mathematical theory of | Dirac monopole | Discrete analysis | Discrete programming | Discrete space-time | D-module | Double-periodic function | Double plane | Duality | Duality in complex analysis | Dynamical system | Dynamical systems software packages | Edge of regression | Ehresmann connection | Eikonal equation | Elliptic integral | Envelope | Euler-Lagrange equation | Euler-Poisson-Darboux equation | Excellent ring | Extension theorems | Fejér polynomial | Finitely-determined function | Finite-to-one mapping | Flag structure | Fold | Foliation | Fourier hyperfunction | Fourier integral operator | Fraïssé characterization of elementary equivalence | Fredholm solvability | Frobenius theorem on Pfaffian systems | Fuchsian equation | Function of exponential type | Gas dynamics, numerical methods of | Gauss-Manin connection | Gel'fond-Schneider method | Generalized function algebras | General position | Generating operator of a semi-group | Geometric approximation | Geometric measure theory | Geometry | Geometry in the large | Germ | Gevrey class | Grammar form | Gravitation, theory of | Green function | Hadamard theorem | Haefliger structure | Harmonic function | Harmonic mapping | Hartogs theorem | Hilbert problems | Hodge structure | Homoclinic bifurcations | Homogeneous convex cone | Horocycle flow | H-principle | Huygens principle | Hyperbolic partial differential equation, numerical methods | Hypergeometric equation | Hypersurface | Immersion | Index formulas | Index theory | Integral manifold | Integral representation of an analytic function | Integral representations in multi-dimensional complex analysis | Intermediate Jacobian | Intersection homology | Invariant set | Invariants, theory of | Isolated singular point | Isometric immersion | Isoperimetric inequality | Jacobi variety | Jet | Jordan matrix | Kähler-Einstein manifold | Kawamata rationality theorem | Kawamata-Viehweg vanishing theorem | K-contact-flow | Kempf vanishing theorem | Kneser theorem | Knot theory | Kontsevich integral | Künneth formula | Lamination | Laurent series | Legendre manifold | Lewy operator and Mizohata operator | Lie algebroid | Limit cycle | Linear algebra software packages | Linear differential equation in a Banach space | Linear hyperbolic partial differential equation and system | Linear system | Local tomography | Local uniformization | Manifold | Many-valued logic | Massless field | Mathematical ecology | Meromorphic function | Method of characteristics | Minimal model | Minimal set | Minimal surface | Mittag-Leffler theorem | Model for calculations | Moment problem | Monge-Ampère equation | Monodromy transformation | Monoidal transformation | Mori theory of extremal rays | Morse lemma | Morse-Smale system | Morse theory | Movable singular point | Naked singularity | Negative curvature, surface of | Nevanlinna-Pick interpolation | Non-linear dynamics | Non-linear oscillations | Non-self-adjoint operator | Normal analytic space | Normal form | Open book decomposition | Operator vessel | Orbit | Padé approximation | Painlevé-type equations | Papperitz equation | Penrose cosmic censorship | Perfect normal form | Periodic point | Periodic solution | Period mapping | Pesin theory | Pfaffian problem | Phase space | Plane real algebraic curve | Plücker formulas | Poincaré-Bendixson theory | Poincaré-Dulac theorem | Poincaré return map | Polynomial convexity | Predator-prey system | Prenex formula | Pseudo-differential operator | Pseudo-group | Pseudo-manifold | Pseudo-Riemannian space | Quadratic differential | Quadrature-sum method | Qualitative theory of differential equations in Banach spaces | Quasi-averages, method of | Radiative transfer theory | Rational mapping | Rational singularity | Real algebraic variety | Recursions of higher degrees | Reduced normal form | Regularization | Regular ring (in commutative algebra) | Regular scheme | Relativistic astrophysics, mathematical problems in | Relaxation oscillation | Removable set | Representation of a topological group | Residue form | Residue of an analytic function | Resolution of singularities | Resonance terms | Riemann surface | Riemann surfaces, conformal classes of | Riemann theorem | Root system | Rosinger nowhere-dense generalized function algebra | Saddle-node bifurcation | Sard theorem | Satake compactification | Schwarz alternating method | Seifert conjecture | Seifert fibration | Semi-algebraic set | Semi-group of operators | Singular integral equation | Singularities of differentiable mappings | Singularity | Singular point | Small parameter, method of the | Spectral theory | Spectral theory of differential operators | Stationary phase, method of the | Statistical mechanics, mathematical problems in | Statistical physics, mathematical problems in | Steenrod problem | Stefan problem | Steklov problems | Submanifold | Subvariety, involutive | Symmetric function | System of subvarieties | Szegö limit theorems | Tacnode | Tangent cone | Taylor joint spectrum | Teichmüller mapping | Thom-Boardman singularities | Thom–Boardman singularities | Thom catastrophes | Tight and taut immersions | Toeplitz C*-algebra | Topological dynamics | Train track | Turbulence, mathematical problems in | Turbulent system | Two-dimensional manifold of bounded curvature | Two-dimensional problems in fracture mechanics | Undecidability | Unipotent element | Universal behaviour in dynamical systems | Vanishing cycle | Variation of Hodge structure | Vector field on a manifold | Wave front | Weak singularity | Weierstrass point | Weierstrass theorem | Weil algebra of a Lie algebra | Weyl algebra | Weyl calculus | Weyl quantization | Whitney extension theorem | Wiener field | Zariski-Lipman conjecture | Zonal harmonics |

## Your userpage and categories

Sergei, you'd better use the "MSCwiki" template on your userpage; the "MSC" template gives a category to your userpage, which should not happen; as far as I understand, only articles should have categories. By the way, if you want to only *mention* a category, you can do it like this: Category:Ordinary differential equations. --Boris Tsirelson 21:56, 5 May 2012 (CEST)

- Done. Thanks! BTW, I still hesitate how to deal with multiple "Primary" classification. Ulf corrected me that MSN indeed requires only one primary class, so apparently either my memory betrayed me, or the editors of MR did the last choice for me...
- Yes, I also feel such a problem. I knew that only one primary is allowed by MR (no, it is not a novelty), but it makes some troubles. Sometimes I gave a secondary class only because I could not give another primary. But I was prepared to have troubles; every classification makes troubles (is there some Goedel-type theorem for it?);
- No, Boris, it's Zermelo: Your problem is discussed here:) --Ulf Rehmann 10:42, 6 May 2012 (CEST)
- ?? --Boris Tsirelson 13:38, 6 May 2012 (CEST)

- Oh well, for every EoM page $p$ you have the set $C(p)$ of possible classifications, now by Zermelo you know there is a function $C(p) \mapsto c_p\in C(p)$ to pick one to get $p\mapsto c_p$, however, Zermelo is not constructive... (Sorry Sergei for spamming your talk page with nonsense... feel free to delete this). --Ulf Rehmann 15:01, 6 May 2012 (CEST)

- No, Boris, it's Zermelo: Your problem is discussed here:) --Ulf Rehmann 10:42, 6 May 2012 (CEST)
- and they are much harder (at least for me) when I finish a paper; sometimes I cannot find any appropriate class at all. Encyclopedic articles are better in this aspect, and no wonder: they describe existing topics, while papers can also introduce new topics. --Boris Tsirelson 07:40, 6 May 2012 (CEST)
- Boris, my hesitation comes from pages which contain an intrinsic disambiguation. For instance, the Node (unfinished job) may mean either nodal singularity of a curve, a singularity of a vector field, a point in the interpolation scheme etc. Of course, one could write separate pages and give them the different codes, yet this would result in atomization of EoM. I personally prefer the Britannica-style where a page (article) is a subject for reading rather than a few lines of dictionary-like definition so characteristic of БСЭ and Webster. In this respect it would be better to write longer pages if they have some common math genetics. -- Sergei Yakovenko 07:47, 6 May 2012 (CEST)
- You may as well put in two or more MSC lines. I used the MSN conditions for the template, because this way I could make use of the capabilities of the MSN parser for the classification semantics. I wished the MSCwiki would offer such a parser as well. --Ulf Rehmann 10:42, 6 May 2012 (CEST)

- I also like "a subject for reading rather than a few lines of dictionary-like definition". But it does not mean that I like "pages which contain an intrinsic disambiguation". As for me, several closely related topics (with quite different names) coexist well in an article; but weakly related topics with similar (or even identical) names do not. For example, "Measurable space" is rather long; but "Measure algebra" is a disambiguation page, and does not need MSC classification. --Boris Tsirelson 13:38, 6 May 2012 (CEST)

- Boris, my hesitation comes from pages which contain an intrinsic disambiguation. For instance, the Node (unfinished job) may mean either nodal singularity of a curve, a singularity of a vector field, a point in the interpolation scheme etc. Of course, one could write separate pages and give them the different codes, yet this would result in atomization of EoM. I personally prefer the Britannica-style where a page (article) is a subject for reading rather than a few lines of dictionary-like definition so characteristic of БСЭ and Webster. In this respect it would be better to write longer pages if they have some common math genetics. -- Sergei Yakovenko 07:47, 6 May 2012 (CEST)

- Yes, I also feel such a problem. I knew that only one primary is allowed by MR (no, it is not a novelty), but it makes some troubles. Sometimes I gave a secondary class only because I could not give another primary. But I was prepared to have troubles; every classification makes troubles (is there some Goedel-type theorem for it?);

- Probably, I need to overcome some newly acquired phobia: once I learned that only Ulf has the privilege to delete pages, I grew very reluctant to create new pages. Thus, if I see a page like Isotopy, I would add to it the second meaning rather than create two different pages. Some navel gazing reuired... :-) Sergei Yakovenko 14:00, 6 May 2012 (CEST)
- Well, we cannot delete a page, but we can make it empty, or replace it with "This page is to be deleted", or (better) replace it with a redirect page; the latter form of extermination is widely used on Wikipedia. --Boris Tsirelson 17:23, 6 May 2012 (CEST)

- Probably, I need to overcome some newly acquired phobia: once I learned that only Ulf has the privilege to delete pages, I grew very reluctant to create new pages. Thus, if I see a page like Isotopy, I would add to it the second meaning rather than create two different pages. Some navel gazing reuired... :-) Sergei Yakovenko 14:00, 6 May 2012 (CEST)

**How to Cite This Entry:**

Yakovenko.

*Encyclopedia of Mathematics.*URL: http://encyclopediaofmath.org/index.php?title=Yakovenko&oldid=26127