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Åhag, Per
Publications (10 of 11) Show all publications
Åhag, P., Cegrell, U. & Hoang Hiep, P. (2010). A PRODUCT PROPERTY FOR THE PLURICOMPLEX ENERGY. Osaka Journal of Mathematics, 47(3), 637-650
Open this publication in new window or tab >>A PRODUCT PROPERTY FOR THE PLURICOMPLEX ENERGY
2010 (English)In: Osaka Journal of Mathematics, ISSN 0030-6126, Vol. 47, no 3, p. 637-650Article in journal (Refereed) Published
Abstract [en]

In this note we prove a product property for the pluricomplex energy, and then give some applications.

Keywords
PLURISUBHARMONIC-FUNCTIONS
National Category
Mathematics
Identifiers
urn:nbn:se:miun:diva-13478 (URN)000285678700003 ()2-s2.0-77958608528 (Scopus ID)
Available from: 2011-04-06 Created: 2011-04-06 Last updated: 2025-09-25Bibliographically approved
Åhag, P. & Czyz, R. (2010). Modulability and duality of certain cones in pluripotential theory. Journal of Mathematical Analysis and Applications, 361(2), 302-321
Open this publication in new window or tab >>Modulability and duality of certain cones in pluripotential theory
2010 (English)In: Journal of Mathematical Analysis and Applications, ISSN 0022-247X, E-ISSN 1096-0813, Vol. 361, no 2, p. 302-321Article in journal (Refereed) Published
Abstract [en]

Let p>0, and let

denote the cone of negative plurisubharmonic functions with finite pluricomplex p-energy. We prove that the vector space

, with the vector ordering induced by the cone

is σ-Dedekind complete, and equipped with a suitable quasi-norm it is a non-separable quasi-Banach space with a decomposition property with control of the quasi-norm. Furthermore, we explicitly characterize its topological dual. The cone

in the quasi-normed space

is closed, generating, and has empty interior.

Keywords
Cone; δ-plurisubharmonic function; Modulability; Ordered vector space; Quasi-Banach space; Topological dual
National Category
Mathematics
Identifiers
urn:nbn:se:miun:diva-9597 (URN)10.1016/j.jmaa.2009.07.013 (DOI)000270865400003 ()2-s2.0-70349758122 (Scopus ID)
Available from: 2009-09-01 Created: 2009-09-01 Last updated: 2025-09-25Bibliographically approved
Åhag, P. & Czyz, R. (2009). An Inequality for the Beta Function with Application to Pluripotential Theory. Journal of inequalities and applications, 2009, Article ID 901397.
Open this publication in new window or tab >>An Inequality for the Beta Function with Application to Pluripotential Theory
2009 (English)In: Journal of inequalities and applications, ISSN 1025-5834, E-ISSN 1029-242X, Vol. 2009, article id 901397Article in journal (Refereed) Published
Abstract [en]

We prove in this paper an inequality for the beta function, and we give an application in pluripotential theory.

National Category
Mathematics
Identifiers
urn:nbn:se:miun:diva-10190 (URN)10.1155/2009/901397 (DOI)000270607300001 ()2-s2.0-70349224022 (Scopus ID)
Available from: 2009-10-26 Created: 2009-10-26 Last updated: 2025-09-25Bibliographically approved
Åhag, P. (2007). A Dirichlet problem for the complex Monge-Ampere operator in F(f). The Michigan mathematical journal, 55(1), 123-138
Open this publication in new window or tab >>A Dirichlet problem for the complex Monge-Ampere operator in F(f)
2007 (English)In: The Michigan mathematical journal, ISSN 0026-2285, E-ISSN 1945-2365, Vol. 55, no 1, p. 123-138Article in journal (Refereed) Published
National Category
Mathematics
Identifiers
urn:nbn:se:miun:diva-8463 (URN)10.1307/mmj/1177681988 (DOI)000246978200007 ()2-s2.0-34250866259 (Scopus ID)
Available from: 2009-01-26 Created: 2009-01-26 Last updated: 2025-09-25Bibliographically approved
Åhag, P., Czyz, R. & Hiep, P. H. (2007). Concerning the energy class epsilon(p) for 0 < p < 1. Paper presented at International Summer School in Several Complex Variables, Jun 19-23, 2006, Szczyrk, Poland. Annales Polonici Mathematici, 91(2-3), 119-130
Open this publication in new window or tab >>Concerning the energy class epsilon(p) for 0 < p < 1
2007 (English)In: Annales Polonici Mathematici, ISSN 0066-2216, E-ISSN 1730-6272, Vol. 91, no 2-3, p. 119-130Article in journal (Refereed) Published
Abstract [en]

The energy class S, is studied for 0 < p < 1. A characterization of certain bounded plurisubharmonic functions in terms of F, and its pluricomplex p-energy is proved.

Keywords
MONGE-AMPERE OPERATOR; PLURISUBHARMONIC-FUNCTIONS
National Category
Mathematics
Identifiers
urn:nbn:se:miun:diva-11849 (URN)000255160600003 ()
Conference
International Summer School in Several Complex Variables, Jun 19-23, 2006, Szczyrk, Poland
Note
International Summer School in Several Complex Variables, Jun 19-23, 2006, Szczyrk, PolandAvailable from: 2010-07-14 Created: 2010-07-14 Last updated: 2025-09-25Bibliographically approved
Åhag, P. & Czyz, R. (2007). Continuous pluriharmonic boundary values. Paper presented at International Summer School in Several Complex Variables, Jun 19-23, 2006, Szczyrk, Poland. Annales Polonici Mathematici, 91(2-3), 99-117
Open this publication in new window or tab >>Continuous pluriharmonic boundary values
2007 (English)In: Annales Polonici Mathematici, ISSN 0066-2216, E-ISSN 1730-6272, Vol. 91, no 2-3, p. 99-117Article in journal (Refereed) Published
Abstract [en]

Let D-j be a bounded hyperconvex domain in C-nj and set D = D-1 x ..... x D-s, j = 1,...,s, s >= 3. Also let G(n) be the symmetrized polydisc in C-n, n >= 3. We characterize those real-valued continuous functions defined on the boundary of D or G. which can be extended to the inside to a pluriharmonic function. As an application a complete characterization of the compliant functions is obtained.

Keywords
MONGE-AMPERE OPERATOR; PLURISUBHARMONIC-FUNCTIONS; SYMMETRIZED BIDISC; DIRICHLET PROBLEM; GEOMETRY; EQUATION
National Category
Mathematics
Identifiers
urn:nbn:se:miun:diva-11848 (URN)000255160600002 ()
Conference
International Summer School in Several Complex Variables, Jun 19-23, 2006, Szczyrk, Poland
Note
International Summer School in Several Complex Variables, Jun 19-23, 2006, Szczyrk, PolandAvailable from: 2010-07-14 Created: 2010-07-14 Last updated: 2025-09-25Bibliographically approved
Åhag, P. & Czyz, R. (2007). On the Cegrell classes. Mathematische Zeitschrift, 256(2), 243-264
Open this publication in new window or tab >>On the Cegrell classes
2007 (English)In: Mathematische Zeitschrift, ISSN 0025-5874, E-ISSN 1432-1823, Vol. 256, no 2, p. 243-264Article in journal (Refereed) Published
Abstract [en]

The Cegrell classes with zero boundary data are defined by certain decreasing approximating sequences of functions with different properties depending on the class in question. It is different for Cegrell classes which are given by a continuous function f, these classes are defined by an inequality. It is proved in this article that it is possible to define the Cegrell classes which are given by f in a similar manner as those classes with zero boundary data. An existence result for the Dirichlet problem for certain singular measures is proved. The article ends with three applications. Results connected to convergence in capacity, subextension of plurisubharmonic functions and integrability are proved.

Keywords
Complex Monge-Ampère operator, Dirichlet problem, Plurisubharmonic function
National Category
Mathematics
Identifiers
urn:nbn:se:miun:diva-8464 (URN)10.1007/s00209-006-0067-2 (DOI)000245854600002 ()2-s2.0-33947326069 (Scopus ID)
Available from: 2009-01-26 Created: 2009-01-26 Last updated: 2025-09-25Bibliographically approved
Åhag, P., Czyz, R., Lodin, S. & Wikström, F. (2007). Plurisubharmonic extension in non-degenerate analytic polyhedra. Universitatis Iagellonicae Acta Mathematica (45), 139-145
Open this publication in new window or tab >>Plurisubharmonic extension in non-degenerate analytic polyhedra
2007 (English)In: Universitatis Iagellonicae Acta Mathematica, ISSN 0860-0120, no 45, p. 139-145Article in journal (Refereed) Published
Abstract [en]

Let $mathcal{P}$ be a connected, non-degenerate analytic polyhedron in $mathbb{C}^n$, $ngeq 2$. In this note we characterize those continuous functions which can be extended to a plurisubharmonic function in $mathcal{P}$.

Keywords
analytic discs, analytic polyhedra, Dirichlet problem, Jensen measures, plurisubharmonic functions
National Category
Mathematics
Identifiers
urn:nbn:se:miun:diva-4385 (URN)5294 (Local ID)5294 (Archive number)5294 (OAI)
Available from: 2008-09-30 Created: 2009-09-15 Last updated: 2025-09-25Bibliographically approved
Gidlund, M. & Åhag, P. (2004). Enhanced HARQ Scheme based on Rearrangement of Signal Constellations and Frequency Diversity for OFDM Systems. In: VTC2004-SPRING: 2004 IEEE 59TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-5, PROCEEDINGS. Paper presented at 59th IEEE Vehicular Technology Conference, May 17-19, 2004, Milan, Italy (pp. 500-504). IEEE
Open this publication in new window or tab >>Enhanced HARQ Scheme based on Rearrangement of Signal Constellations and Frequency Diversity for OFDM Systems
2004 (English)In: VTC2004-SPRING: 2004 IEEE 59TH VEHICULAR TECHNOLOGY CONFERENCE, VOLS 1-5, PROCEEDINGS, IEEE , 2004, p. 500-504Conference paper, Published paper (Refereed)
Abstract [en]

In multi-carrier modulation systems such as OFDM, several subcarriers are used for transmission and their received signal quality is different from one subcarrier to others in frequency selective fading channel. In this paper an enhanced hybrid ARQ scheme for OFDM systems is proposed. When data is requested for retransmissions, we change the bit interleaving mode in such manner that the data sequence is changed. Since the coded bit is assigned to different subcarriers and positions of a modulation symbols in different retransmissions we can take advantage of this effect, and achieve both frequency- and modulation constellation diversity. Results from computer simulations confirm that the proposed scheme improves the throughput performance. After two transmissions and with packet error rate (PER) of 10(-4) the proposed scheme gain approximate 3 dB compared to a scheme emploving Chase combining. The performance gain is even more for three transmissions (2 retransmissions).

Place, publisher, year, edition, pages
IEEE, 2004
Keywords
OFDM, Signal Constellation, Diversity
National Category
Computer Sciences
Identifiers
urn:nbn:se:miun:diva-2594 (URN)000226279400104 ()1955 (Local ID)0-7803-8255-2 (ISBN)1955 (Archive number)1955 (OAI)
Conference
59th IEEE Vehicular Technology Conference, May 17-19, 2004, Milan, Italy
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2025-09-25Bibliographically approved
Gidlund, M. & Åhag, P. (2003). A CRC-based Link Adaptation Algorithm for IEEE 802.11a Wireless LAN. In: Proceedings of the 2003 IEEE Asia-Pacific Conference on Communications (APCC 2003).
Open this publication in new window or tab >>A CRC-based Link Adaptation Algorithm for IEEE 802.11a Wireless LAN
2003 (English)In: Proceedings of the 2003 IEEE Asia-Pacific Conference on Communications (APCC 2003), 2003Conference paper, Published paper (Other academic)
Keywords
WLAn, Link adaptation
National Category
Computer Sciences
Identifiers
urn:nbn:se:miun:diva-1748 (URN)426 (Local ID)426 (Archive number)426 (OAI)
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2025-09-25Bibliographically approved
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