Yuval Ginosar - Academia.edu (original) (raw)

Papers by Yuval Ginosar

We suggest an alternative proof of a theorem due to Lambek and Moser using a perceptible model.

Bulletin of the London Mathematical Society, 2014

The analogue of Lagrangians for symplectic forms over finite groups is studied, motivated by the ... more The analogue of Lagrangians for symplectic forms over finite groups is studied, motivated by the fact that symplectic G-forms with a normal Lagrangian N ⊳G are in one-to-one correspondence, up to inflation, with bijective 1-cocycle data on the quotients G/N . This yields a method to construct groups of central type from such quotients, known as Involutive Yang-Baxter groups. Another motivation for the search of normal Lagrangians comes from a noncommutative generalization of Heisenberg liftings which require normality.

Chem Phys Lett, 2008

Let G be a graph whose eigenvalues are λ1, λ2,…, λn. The Estrada index of G is equal to ∑i=1ne. W... more Let G be a graph whose eigenvalues are λ1, λ2,…, λn. The Estrada index of G is equal to ∑i=1ne. We point out certain classes of graphs whose characteristic polynomials are closely connected to the Chebyshev polynomials of the second kind. Various relations, in particular approximations, for the Estrada index of these graphs are obtained.

We suggest an alternative proof of a theorem due to Lambek and Moser using a perceptible model.

Proceedings of the American Mathematical Society, 2008

The Donald-Flanigan conjecture asserts that for any finite group G and any field k, the group alg... more The Donald-Flanigan conjecture asserts that for any finite group G and any field k, the group algebra kG can be deformed to a separable algebra. The minimal unsolved instance, namely the quaternion group Q 8 over a field k of characteristic 2 was considered as a counterexample. We present here a separable deformation of kQ 8 . In a sense, the conjecture for any finite group is open again.

Discrete Mathematics, 2015

ABSTRACT Any simple group-grading of a finite dimensional complex algebra induces a natural famil... more ABSTRACT Any simple group-grading of a finite dimensional complex algebra induces a natural family of digraphs. We prove that ∣EcircEtextopcupEtextopcircE∣geq∣E∣|E\circ E^{\text{op}}\cup E^{\text{op}}\circ E|\geq |E|∣EcircEtextopcupEtextopcircE∣geq∣E∣ for any digraph Gamma=(V,E)\Gamma =(V,E)Gamma=(V,E) without parallel edges, and deduce that for any simple group-grading, the dimension of the trivial component is maximal.

Chapman & Hall/CRC Mathematical & Computational Biology, 2003

... w/links (466 KB). Chapter 11. Cancer Immune System Competition Nicola Bellomo, Maria Letizia ... more ... w/links (466 KB). Chapter 11. Cancer Immune System Competition Nicola Bellomo, Maria Letizia Bertotti, Santo Motta Abstract - Hi-Res PDF (536 KB) - PDF w/links (544 KB). Chapter 12. Analysing Hypersensitivity to Chemotherapy ...

Chapman & Hall/CRC Mathematical & Computational Biology, 2003

... Angiogenic Dynamics and Therapy Levon Arakelyan, Yifat Merbl, Peteris Daugulis, Yuval Ginosar... more ... Angiogenic Dynamics and Therapy Levon Arakelyan, Yifat Merbl, Peteris Daugulis, Yuval Ginosar, Vladimir Vainstein, Vera Selitser, Yuri Kogan, Hila Harpak, and Zvia Agur Institute for Medical Biomathematics (IMBM), Bene Ataroth (Israel) 7.1 Introduction ...

Proceedings of the American Mathematical Society, 2007

Abstract. We first deal with classical crossed products Sf ∗ G, where G is a finite group acting ... more Abstract. We first deal with classical crossed products Sf ∗ G, where G is a finite group acting on a Dedekind domain S and SG (the G-invariant elements in S) a DVR, admitting a separable residue fields extension. Here f : G × G → S * is a 2-cocycle. We prove that Sf ∗ G is ...

Journal of Pure and Applied Algebra, 2007

Let A * Γ be a crossed product algebra, where A is semisimple, finitely generated over its center... more Let A * Γ be a crossed product algebra, where A is semisimple, finitely generated over its center and Γ is a finite group. We give a necessary and sufficient condition in terms of the outer action of Γ on A for the existence of a multi-parametric semisimple deformation of the form A((t 1 , . . . , t n )) * Γ (with the induced outer action). The main tool in the proof is the solution of the so-called twisting problem. We also give an example which shows that the condition is not sufficient if one drops the condition on the finite generation of A over its center.

Journal of Pure and Applied Algebra, 1996

Journal of Mathematical Biology, 2002

CITATIONS 44 READS 75 3 authors, including:

Israel Journal of Mathematics, 2009

A finite group G is of central type (in the non-classical sense) if it admits a non-degenerate co... more A finite group G is of central type (in the non-classical sense) if it admits a non-degenerate cohomology class [c]

Discrete Mathematics, 2000

We consider the following dynamic process on the 0 -1 colourings of the vertices of a graph. The ... more We consider the following dynamic process on the 0 -1 colourings of the vertices of a graph. The initial state is an arbitrary colouring, and the state at time t + 1 is determined by assigning to each vertex the colour of the majority of its neighbours at time t (in case of a tie, the vertex retains its own colour at time t). It is known that if the graph is ÿnite then the process either reaches a ÿxed colouring or becomes periodic with period two. Here we show that an inÿnite (locally ÿnite) graph displays the same behaviour locally, provided that the graph satisÿes a certain condition which, roughly speaking, imposes an upper bound on the growth rate of the graph. Among the graphs obeying this condition are some that are most common in applications, such as the grid graph in two or more dimensions. We also extend the analysis to more general dynamic processes, and compare our results to the seminal work of Moran in this area.

We suggest an alternative proof of a theorem due to Lambek and Moser using a perceptible model.

Bulletin of the London Mathematical Society, 2014

The analogue of Lagrangians for symplectic forms over finite groups is studied, motivated by the ... more The analogue of Lagrangians for symplectic forms over finite groups is studied, motivated by the fact that symplectic G-forms with a normal Lagrangian N ⊳G are in one-to-one correspondence, up to inflation, with bijective 1-cocycle data on the quotients G/N . This yields a method to construct groups of central type from such quotients, known as Involutive Yang-Baxter groups. Another motivation for the search of normal Lagrangians comes from a noncommutative generalization of Heisenberg liftings which require normality.

Chem Phys Lett, 2008

Let G be a graph whose eigenvalues are λ1, λ2,…, λn. The Estrada index of G is equal to ∑i=1ne. W... more Let G be a graph whose eigenvalues are λ1, λ2,…, λn. The Estrada index of G is equal to ∑i=1ne. We point out certain classes of graphs whose characteristic polynomials are closely connected to the Chebyshev polynomials of the second kind. Various relations, in particular approximations, for the Estrada index of these graphs are obtained.

We suggest an alternative proof of a theorem due to Lambek and Moser using a perceptible model.

Proceedings of the American Mathematical Society, 2008

The Donald-Flanigan conjecture asserts that for any finite group G and any field k, the group alg... more The Donald-Flanigan conjecture asserts that for any finite group G and any field k, the group algebra kG can be deformed to a separable algebra. The minimal unsolved instance, namely the quaternion group Q 8 over a field k of characteristic 2 was considered as a counterexample. We present here a separable deformation of kQ 8 . In a sense, the conjecture for any finite group is open again.

Discrete Mathematics, 2015

ABSTRACT Any simple group-grading of a finite dimensional complex algebra induces a natural famil... more ABSTRACT Any simple group-grading of a finite dimensional complex algebra induces a natural family of digraphs. We prove that ∣EcircEtextopcupEtextopcircE∣geq∣E∣|E\circ E^{\text{op}}\cup E^{\text{op}}\circ E|\geq |E|∣EcircEtextopcupEtextopcircE∣geq∣E∣ for any digraph Gamma=(V,E)\Gamma =(V,E)Gamma=(V,E) without parallel edges, and deduce that for any simple group-grading, the dimension of the trivial component is maximal.

Chapman & Hall/CRC Mathematical & Computational Biology, 2003

... w/links (466 KB). Chapter 11. Cancer Immune System Competition Nicola Bellomo, Maria Letizia ... more ... w/links (466 KB). Chapter 11. Cancer Immune System Competition Nicola Bellomo, Maria Letizia Bertotti, Santo Motta Abstract - Hi-Res PDF (536 KB) - PDF w/links (544 KB). Chapter 12. Analysing Hypersensitivity to Chemotherapy ...

Chapman & Hall/CRC Mathematical & Computational Biology, 2003

... Angiogenic Dynamics and Therapy Levon Arakelyan, Yifat Merbl, Peteris Daugulis, Yuval Ginosar... more ... Angiogenic Dynamics and Therapy Levon Arakelyan, Yifat Merbl, Peteris Daugulis, Yuval Ginosar, Vladimir Vainstein, Vera Selitser, Yuri Kogan, Hila Harpak, and Zvia Agur Institute for Medical Biomathematics (IMBM), Bene Ataroth (Israel) 7.1 Introduction ...

Proceedings of the American Mathematical Society, 2007

Abstract. We first deal with classical crossed products Sf ∗ G, where G is a finite group acting ... more Abstract. We first deal with classical crossed products Sf ∗ G, where G is a finite group acting on a Dedekind domain S and SG (the G-invariant elements in S) a DVR, admitting a separable residue fields extension. Here f : G × G → S * is a 2-cocycle. We prove that Sf ∗ G is ...

Journal of Pure and Applied Algebra, 2007

Let A * Γ be a crossed product algebra, where A is semisimple, finitely generated over its center... more Let A * Γ be a crossed product algebra, where A is semisimple, finitely generated over its center and Γ is a finite group. We give a necessary and sufficient condition in terms of the outer action of Γ on A for the existence of a multi-parametric semisimple deformation of the form A((t 1 , . . . , t n )) * Γ (with the induced outer action). The main tool in the proof is the solution of the so-called twisting problem. We also give an example which shows that the condition is not sufficient if one drops the condition on the finite generation of A over its center.

Journal of Pure and Applied Algebra, 1996

Journal of Mathematical Biology, 2002

CITATIONS 44 READS 75 3 authors, including:

Israel Journal of Mathematics, 2009

A finite group G is of central type (in the non-classical sense) if it admits a non-degenerate co... more A finite group G is of central type (in the non-classical sense) if it admits a non-degenerate cohomology class [c]

Discrete Mathematics, 2000

We consider the following dynamic process on the 0 -1 colourings of the vertices of a graph. The ... more We consider the following dynamic process on the 0 -1 colourings of the vertices of a graph. The initial state is an arbitrary colouring, and the state at time t + 1 is determined by assigning to each vertex the colour of the majority of its neighbours at time t (in case of a tie, the vertex retains its own colour at time t). It is known that if the graph is ÿnite then the process either reaches a ÿxed colouring or becomes periodic with period two. Here we show that an inÿnite (locally ÿnite) graph displays the same behaviour locally, provided that the graph satisÿes a certain condition which, roughly speaking, imposes an upper bound on the growth rate of the graph. Among the graphs obeying this condition are some that are most common in applications, such as the grid graph in two or more dimensions. We also extend the analysis to more general dynamic processes, and compare our results to the seminal work of Moran in this area.