Tarek Ahmed - Profile on Academia.edu (original) (raw)
Papers by Tarek Ahmed
Advanced High Power DC-DC Converter using Novel Type Half-Bridge Soft Switching PWM Inverter with High Frequency Transformer for Arc Welder
Power Electronics and …, 2004
Page 1. IEEE PEDS 2005 Advanced High Power DC-DC Converter using Novel Type Half-Bridge Soft Swit... more Page 1. IEEE PEDS 2005 Advanced High Power DC-DC Converter using Novel Type Half-Bridge Soft Switching PWM Inverter with High Frequency Transformer for Arc Welder Keiki Morimoto Nabil A. Ahmed Hyun - Woo Lee Toshimitsu Doi Mutsuo Nakaoka ...
Power Electronics and …, 2004
This paper presents a new circuit topology of dc bus converter with active switches in the primar... more This paper presents a new circuit topology of dc bus converter with active switches in the primary side of high line switch-assisted half-bridge soft switching PWM inverter type frequency transformer is considered to be more suitable and dc-dc converter for arc welder. The proposed power converter is composed of typical voltage source half-bridge high frequency accele.Aa circuit topologytf PWM inverter with a high frequency transformer link in addition arc welder, authors developed the novel circuit topology of to dc bus line side power semiconductor switching devices for voltage source full-bridge type soft switching PWM inverter in PWM control scheme and capacitive lossless snubbers. All the which all the active switches can actively achieve ZCS turn-on active power switches in the half-bridge arm and dc bus lines can and ZVS turn-off commutation operation [6]-[10]. achieve ZCS turn-on and ZVS turn-off commutation operation and consequently the total turn-off switching losses can be B. Research Objectives significantly reduced. As a result, a high switching frequency of This paper presents a novel circuit topology of voltage using IGBTs can be actually selected more than about 10 kHz. source half-bridge type soft switching PWM inverter. Under The effectiveness of this new converter topology is proved for low the newly-proposed high frequency inverter link dc-dc power voltage and large current dc-dc power supplies such as arc welder circuit, all the active switches in the half-bridge arm and dc bus from a practical point of view. lines can actively achieve ZCS turn-on and ZVS turn-off commutation operation. Keywords-Dc-dc power converter, High frequency transformer The steady state operating principle of the proposed soft link, Soft switching PWM arc welding machine, switching PWM dc-dc power converter is described with its remarkable features. The experimental operation results ofthis I. INTRODUCTION new type of soft switching PWM dc-dc power converter using A. Research Background IGBT power modules are illustrated including power loss Recently, saturable inductor assisted ZVS-PWM full-bridge analysis as compared with that of the hard switching PWM high-frequency inverter link dc-dc power converter [1] and dc-dc power converter. The practical effectiveness of the lossless capacitors and transformer parasitic inductive proposed high frequency transformer link dc-dc power components assisted soft switching dc-dc power converter with converter acceptable and suitable for high power applications phase-shifted modulation control scheme in secondary-side of which is designed for low voltage and large current output is high frequency transformer [2]-[5] have been developed and
Two field experiments were conducted at Farm, El-Kanater Horticultural Research Station, Kalubeia... more Two field experiments were conducted at Farm, El-Kanater Horticultural Research Station, Kalubeia Governorate during two successive seasons (2013 and 2014) to study the effect three level of soil moisture depleted available water, (A.S.M.D) 20, 40 and60% on some water relations, water use efficiency, vegetative growth, yield and fruit quality, cultivating fruitful trees of " peach (Meet Ghamr and Florida prince cultivars). The main results can be summarized as follows:
A two-year field experiment was conducted at El-Kanater Horticultural Research Station in the 201... more A two-year field experiment was conducted at El-Kanater Horticultural Research Station in the 2010 and 2011 seasons. This study aimed to determine the effect of the change from surface irrigation to drip irrigation on seasonal applied irrigation water, consumptive use, yield, growth, flowering and fruiting of three plum trees varieties. Plum trees which had been irrigated by surface irrigation for many years was used for the study, during which drip irrigation was applied in one section, while surface irrigation was continued for rest of the plum orchard. Results for surface irrigation system showed higher applied irrigation water (5180 & 5124 m 3 /feddan/year) than the drip irrigation system (2607 & 2553 m 3 /feddan/year) during 2010 and 2011 seasons, respectively. Drip irrigation system supported an increase of water productivity (1.94 and 2.5 kg fruits/m 3 ). Moreover, drip irrigation system proved superiority in enhancing the studied tree growth, root system distribution, fruiting and fruit quality parameters as well as weed control than surface irrigation system. However, the three studied plum cultivars showed variability in their response to the prospective effects of drip irrigation system .
International Journal of Nanomedicine, 2015
A Novel Induction Generator System for Small-Scale AC and DC Power Applications
IEEE 36th Conference on Power Electronics Specialists, 2005., 2005
Abstract-This paper presents a novel dynamic model in the stationary reference frame for a diode ... more Abstract-This paper presents a novel dynamic model in the stationary reference frame for a diode bridge rectifier with a DC-link filter directly connected to a three-phase induction generator (IG). Moreover, a hybrid excitation system, consisting of a capacitor bank and an active ...
The main result gives a sufficient condition for a classK of finite dimensional cylindric algebra... more The main result gives a sufficient condition for a classK of finite dimensional cylindric algebras to have the property that not every epimorphism in K is surjective. In particular, not all epimorphisms are surjective in the classes CAn of n-dimensional cylindric algebras and the class of representable algebras in CAn for finite n > 1, solving Problem 10 of (28)
Advanced Active Power Filter Controlled permanent-magnet synchronous generator for Automotive Applications
2007 IEEE Power Electronics Specialists Conference, 2007
... Advanced Active Power Filter Controlled permanent-magnet synchronous generator for Automotive... more ... Advanced Active Power Filter Controlled permanent-magnet synchronous generator for Automotive Applications Katsumi Nishida Tarek Ahmed Mutsuo Nakaoka Ube National College of Technology ... i l (k) i lu i lv DC Load Rdc Lf Cf ... i cu i cv Phase Locked Loop AC Load Sw ...
A novel current control system using PLL circuit for interior permanent magnet synchronous generator
2008 IEEE Power Electronics Specialists Conference, 2008
Interior permanent magnet synchronous generator (IPMSG) has several advantages such as high effic... more Interior permanent magnet synchronous generator (IPMSG) has several advantages such as high efficiency and high power-to-weight ratio because of its additionally developed reluctance torque. Therefore, a novel IPMSG system using a well-designed phase locked-loop circuit (PLL) and interface filters is proposed. Owing to introducing the two devices, the PLL and interface filters, the direction of the quadrature axis of the
Grid power integration technologies for offshore ocean wave energy
2010 IEEE Energy Conversion Congress and Exposition, 2010
In this paper, the advanced electric technologies for grid power integration of different offshor... more In this paper, the advanced electric technologies for grid power integration of different offshore wave energy conversion devices are presented. The electrical connection configurations for integrating the electric power of the multi wave energy conversion devices such as the Oscillating Water Column, Pelamis, the Wave Point Absorbers and the Wave Dragon are developed by employing the most efficient low cost
Utility Grid Interfaced PV Power Conditioner Using Boost Chopper-Four Switch Three Phase Inverter with a Novel Quasi Resonant DC Link Snubber
Twenty-First Annual IEEE Applied Power Electronics Conference and Exposition, 2006. APEC '06., 2006
... Inverter with A Novel Quasi Resonant DC Link Snubber Tarek Ahmed, Mutsuo Nakaoka Yamaguchi Un... more ... Inverter with A Novel Quasi Resonant DC Link Snubber Tarek Ahmed, Mutsuo Nakaoka Yamaguchi University 2-16-1 Tokiwadai, Ube Yamaguchi, Japan 755-8611 tarek@pe-news1. eee.yamaguchi-u.ac.jp Shinichiro Nagai Sanken Electric Co., Ltd. ...
Development of grid-connected wind energy system employing interior PM Synchronous Generator and multi-pulse rectifier
2010 IEEE Energy Conversion Congress and Exposition, 2010
... Generator and Multi-pulse Rectifier Katsumi Nishida Tarek Ahmed Mutuo Nakaoka ... This scheme... more ... Generator and Multi-pulse Rectifier Katsumi Nishida Tarek Ahmed Mutuo Nakaoka ... This scheme is low cost when compared with the full power converter. When the speed of the generator alters, the voltage value on the dc side of the diode rectifier will change. ...
32 V-300 A/60 kHz edge resonant soft-switching PWM DC/DC converter with DC rail series switch-parallel capacitor snubber assisted by high-frequency transformer parasitic components
The conduction losses of the active switches can be lowered, which are connected to the primary s... more The conduction losses of the active switches can be lowered, which are connected to the primary side of extremely step-down high frequency transformer because of low voltage large current rectifier configuration. This paper presents two new circuit topologies of DC busline side active edge resonant snubber assisted soft-switching PWM full-bridge DC-DC converter acceptable for either utility AC 200 V-rms or
The Edge Effect in Solid Particle Erosion of Ceramic Second-Phase Particles
Key Engineering Materials, 1992
Quasi-Resonant Dual Mode Soft Switching PWM and PDM High-Frequency Inverter with IH Load Resonant Tank
IEEE 36th Conference on Power Electronics Specialists, 2005., 2005
Page 1. Quasi-Resonant Dual Mode Soft Switching PWM and PDM High-Frequency Inverter with IH Load ... more Page 1. Quasi-Resonant Dual Mode Soft Switching PWM and PDM High-Frequency Inverter with IH Load Resonant Tank Nabil A.Ahmed, Ahmad Eid, Hyun Woo Lee and Mutsuo Nakaoka Kyungnam University The Electric Energy ...
Commercial utility frequency AC to high frequency AC soft switching power conversion circuit with non smoothing DC link for IH dual packs heater
The 30th Annual Conference of the lEEE Industrial Electronics Society, November 2 - 6,2004, Busan... more The 30th Annual Conference of the lEEE Industrial Electronics Society, November 2 - 6,2004, Busan, Korea ... Commercial Utility Frequency AC to High Frequency AC Soft Switching Power Conversion Circuit with Non Smoothing DC Llnk for IH Dual Packs Heater
2005 International Conference on Power Electronics and Drives Systems, 2005
In this paper, a novel type of auxiliary switched which may consist of planer (pancake) or cylind... more In this paper, a novel type of auxiliary switched which may consist of planer (pancake) or cylindrical type capacitor assisted edge resonant soft switching PWM series load working coil with electromagnetic eddy current based heated resonant high frequency inverter with two auxiliary edge materials. Consumer IH appliances operating at high resonant lossless inductor snubbers is proposed for small frequency ranges from 20 kHz to several MHz need a cost consumer induction heating appliances. The operation principle of this high frequency inverter is described using the switching effective product, high efficiency and high power density of mode equivalent circuits. This newly developed multi resonant high frequency inverters. Among various types of the high high frequency inverter using trench gate lGBTs can regulate its frequency inverter topologies, there are full bridge, half high frequency output AC power under a principle of constant bridge, single-ended push-pull (SEPP), centre tap push-pull frequency edge-resonant soft switching commutation by and boost-half bridge circuit configurations, in which voltage asymmetrical PWM control scheme. The high frequency power source type lossless snubber inductor assisted zero current regulation and actual power conversion efficiency characteristics soft switching (ZCS) SEPP series load resonant topologies, of consumer brand-new IH products that use the proposed soft voltage source type zero voltage soft switching (ZVS) SEPP switching PWM series load resonant high frequency inverter are resonant inverter and voltage source ZVZCS-SEEP multi evaluated. The practical effectiveness and operating resonant inverter topologies [4]-[8]. These high frequency soft performances of the newly proposed soft switching inverter are song inverter s have The high f soft discussed as compared with the conventional soft switching high switching inverterS have the advantages of simple frequency inverters based on simulation and experimental results configuration, high efficiency, low cost and wide soft from an application point of view.
The Journal of Symbolic Logic, 2008
We give a novel application of algebraic logic to first order logic. A new, flexible construction... more We give a novel application of algebraic logic to first order logic. A new, flexible construction is presented for representable but not completely representable atomic relation and cylindric algebras of dimension n (for finite n > 2) with the additional property that they are one-generated and the set of all n by n atomic matrices forms a cylindric basis. We use this construction to show that the classical Henkin-Orey omitting types theorem fails for the finite variable fragments of first order logic as long as the number of variables available is > 2 and we have a binary relation symbol in our language. We also prove a stronger result to the effect that there is no finite upper bound for the extra variables needed in the witness formulas. This result further emphasizes the ongoing interplay between algebraic logic and first order logic.
Bulletin of Symbolic Logic, 2005
On Complete Representations of Reducts of Polyadic Algebras
Studia Logica, 2008
Abstract Following research initiated by Tarski, Craig and Németi, and futher pursued by Sain and... more Abstract Following research initiated by Tarski, Craig and Németi, and futher pursued by Sain and others, we show that for certain subsets G of ω ω, atomic countable G polyadic algebras are completely representable. G polyadic algebras are obtained by restricting ...
Advanced High Power DC-DC Converter using Novel Type Half-Bridge Soft Switching PWM Inverter with High Frequency Transformer for Arc Welder
Power Electronics and …, 2004
Page 1. IEEE PEDS 2005 Advanced High Power DC-DC Converter using Novel Type Half-Bridge Soft Swit... more Page 1. IEEE PEDS 2005 Advanced High Power DC-DC Converter using Novel Type Half-Bridge Soft Switching PWM Inverter with High Frequency Transformer for Arc Welder Keiki Morimoto Nabil A. Ahmed Hyun - Woo Lee Toshimitsu Doi Mutsuo Nakaoka ...
Power Electronics and …, 2004
This paper presents a new circuit topology of dc bus converter with active switches in the primar... more This paper presents a new circuit topology of dc bus converter with active switches in the primary side of high line switch-assisted half-bridge soft switching PWM inverter type frequency transformer is considered to be more suitable and dc-dc converter for arc welder. The proposed power converter is composed of typical voltage source half-bridge high frequency accele.Aa circuit topologytf PWM inverter with a high frequency transformer link in addition arc welder, authors developed the novel circuit topology of to dc bus line side power semiconductor switching devices for voltage source full-bridge type soft switching PWM inverter in PWM control scheme and capacitive lossless snubbers. All the which all the active switches can actively achieve ZCS turn-on active power switches in the half-bridge arm and dc bus lines can and ZVS turn-off commutation operation [6]-[10]. achieve ZCS turn-on and ZVS turn-off commutation operation and consequently the total turn-off switching losses can be B. Research Objectives significantly reduced. As a result, a high switching frequency of This paper presents a novel circuit topology of voltage using IGBTs can be actually selected more than about 10 kHz. source half-bridge type soft switching PWM inverter. Under The effectiveness of this new converter topology is proved for low the newly-proposed high frequency inverter link dc-dc power voltage and large current dc-dc power supplies such as arc welder circuit, all the active switches in the half-bridge arm and dc bus from a practical point of view. lines can actively achieve ZCS turn-on and ZVS turn-off commutation operation. Keywords-Dc-dc power converter, High frequency transformer The steady state operating principle of the proposed soft link, Soft switching PWM arc welding machine, switching PWM dc-dc power converter is described with its remarkable features. The experimental operation results ofthis I. INTRODUCTION new type of soft switching PWM dc-dc power converter using A. Research Background IGBT power modules are illustrated including power loss Recently, saturable inductor assisted ZVS-PWM full-bridge analysis as compared with that of the hard switching PWM high-frequency inverter link dc-dc power converter [1] and dc-dc power converter. The practical effectiveness of the lossless capacitors and transformer parasitic inductive proposed high frequency transformer link dc-dc power components assisted soft switching dc-dc power converter with converter acceptable and suitable for high power applications phase-shifted modulation control scheme in secondary-side of which is designed for low voltage and large current output is high frequency transformer [2]-[5] have been developed and
Two field experiments were conducted at Farm, El-Kanater Horticultural Research Station, Kalubeia... more Two field experiments were conducted at Farm, El-Kanater Horticultural Research Station, Kalubeia Governorate during two successive seasons (2013 and 2014) to study the effect three level of soil moisture depleted available water, (A.S.M.D) 20, 40 and60% on some water relations, water use efficiency, vegetative growth, yield and fruit quality, cultivating fruitful trees of " peach (Meet Ghamr and Florida prince cultivars). The main results can be summarized as follows:
A two-year field experiment was conducted at El-Kanater Horticultural Research Station in the 201... more A two-year field experiment was conducted at El-Kanater Horticultural Research Station in the 2010 and 2011 seasons. This study aimed to determine the effect of the change from surface irrigation to drip irrigation on seasonal applied irrigation water, consumptive use, yield, growth, flowering and fruiting of three plum trees varieties. Plum trees which had been irrigated by surface irrigation for many years was used for the study, during which drip irrigation was applied in one section, while surface irrigation was continued for rest of the plum orchard. Results for surface irrigation system showed higher applied irrigation water (5180 & 5124 m 3 /feddan/year) than the drip irrigation system (2607 & 2553 m 3 /feddan/year) during 2010 and 2011 seasons, respectively. Drip irrigation system supported an increase of water productivity (1.94 and 2.5 kg fruits/m 3 ). Moreover, drip irrigation system proved superiority in enhancing the studied tree growth, root system distribution, fruiting and fruit quality parameters as well as weed control than surface irrigation system. However, the three studied plum cultivars showed variability in their response to the prospective effects of drip irrigation system .
International Journal of Nanomedicine, 2015
A Novel Induction Generator System for Small-Scale AC and DC Power Applications
IEEE 36th Conference on Power Electronics Specialists, 2005., 2005
Abstract-This paper presents a novel dynamic model in the stationary reference frame for a diode ... more Abstract-This paper presents a novel dynamic model in the stationary reference frame for a diode bridge rectifier with a DC-link filter directly connected to a three-phase induction generator (IG). Moreover, a hybrid excitation system, consisting of a capacitor bank and an active ...
The main result gives a sufficient condition for a classK of finite dimensional cylindric algebra... more The main result gives a sufficient condition for a classK of finite dimensional cylindric algebras to have the property that not every epimorphism in K is surjective. In particular, not all epimorphisms are surjective in the classes CAn of n-dimensional cylindric algebras and the class of representable algebras in CAn for finite n > 1, solving Problem 10 of (28)
Advanced Active Power Filter Controlled permanent-magnet synchronous generator for Automotive Applications
2007 IEEE Power Electronics Specialists Conference, 2007
... Advanced Active Power Filter Controlled permanent-magnet synchronous generator for Automotive... more ... Advanced Active Power Filter Controlled permanent-magnet synchronous generator for Automotive Applications Katsumi Nishida Tarek Ahmed Mutsuo Nakaoka Ube National College of Technology ... i l (k) i lu i lv DC Load Rdc Lf Cf ... i cu i cv Phase Locked Loop AC Load Sw ...
A novel current control system using PLL circuit for interior permanent magnet synchronous generator
2008 IEEE Power Electronics Specialists Conference, 2008
Interior permanent magnet synchronous generator (IPMSG) has several advantages such as high effic... more Interior permanent magnet synchronous generator (IPMSG) has several advantages such as high efficiency and high power-to-weight ratio because of its additionally developed reluctance torque. Therefore, a novel IPMSG system using a well-designed phase locked-loop circuit (PLL) and interface filters is proposed. Owing to introducing the two devices, the PLL and interface filters, the direction of the quadrature axis of the
Grid power integration technologies for offshore ocean wave energy
2010 IEEE Energy Conversion Congress and Exposition, 2010
In this paper, the advanced electric technologies for grid power integration of different offshor... more In this paper, the advanced electric technologies for grid power integration of different offshore wave energy conversion devices are presented. The electrical connection configurations for integrating the electric power of the multi wave energy conversion devices such as the Oscillating Water Column, Pelamis, the Wave Point Absorbers and the Wave Dragon are developed by employing the most efficient low cost
Utility Grid Interfaced PV Power Conditioner Using Boost Chopper-Four Switch Three Phase Inverter with a Novel Quasi Resonant DC Link Snubber
Twenty-First Annual IEEE Applied Power Electronics Conference and Exposition, 2006. APEC '06., 2006
... Inverter with A Novel Quasi Resonant DC Link Snubber Tarek Ahmed, Mutsuo Nakaoka Yamaguchi Un... more ... Inverter with A Novel Quasi Resonant DC Link Snubber Tarek Ahmed, Mutsuo Nakaoka Yamaguchi University 2-16-1 Tokiwadai, Ube Yamaguchi, Japan 755-8611 tarek@pe-news1. eee.yamaguchi-u.ac.jp Shinichiro Nagai Sanken Electric Co., Ltd. ...
Development of grid-connected wind energy system employing interior PM Synchronous Generator and multi-pulse rectifier
2010 IEEE Energy Conversion Congress and Exposition, 2010
... Generator and Multi-pulse Rectifier Katsumi Nishida Tarek Ahmed Mutuo Nakaoka ... This scheme... more ... Generator and Multi-pulse Rectifier Katsumi Nishida Tarek Ahmed Mutuo Nakaoka ... This scheme is low cost when compared with the full power converter. When the speed of the generator alters, the voltage value on the dc side of the diode rectifier will change. ...
32 V-300 A/60 kHz edge resonant soft-switching PWM DC/DC converter with DC rail series switch-parallel capacitor snubber assisted by high-frequency transformer parasitic components
The conduction losses of the active switches can be lowered, which are connected to the primary s... more The conduction losses of the active switches can be lowered, which are connected to the primary side of extremely step-down high frequency transformer because of low voltage large current rectifier configuration. This paper presents two new circuit topologies of DC busline side active edge resonant snubber assisted soft-switching PWM full-bridge DC-DC converter acceptable for either utility AC 200 V-rms or
The Edge Effect in Solid Particle Erosion of Ceramic Second-Phase Particles
Key Engineering Materials, 1992
Quasi-Resonant Dual Mode Soft Switching PWM and PDM High-Frequency Inverter with IH Load Resonant Tank
IEEE 36th Conference on Power Electronics Specialists, 2005., 2005
Page 1. Quasi-Resonant Dual Mode Soft Switching PWM and PDM High-Frequency Inverter with IH Load ... more Page 1. Quasi-Resonant Dual Mode Soft Switching PWM and PDM High-Frequency Inverter with IH Load Resonant Tank Nabil A.Ahmed, Ahmad Eid, Hyun Woo Lee and Mutsuo Nakaoka Kyungnam University The Electric Energy ...
Commercial utility frequency AC to high frequency AC soft switching power conversion circuit with non smoothing DC link for IH dual packs heater
The 30th Annual Conference of the lEEE Industrial Electronics Society, November 2 - 6,2004, Busan... more The 30th Annual Conference of the lEEE Industrial Electronics Society, November 2 - 6,2004, Busan, Korea ... Commercial Utility Frequency AC to High Frequency AC Soft Switching Power Conversion Circuit with Non Smoothing DC Llnk for IH Dual Packs Heater
2005 International Conference on Power Electronics and Drives Systems, 2005
In this paper, a novel type of auxiliary switched which may consist of planer (pancake) or cylind... more In this paper, a novel type of auxiliary switched which may consist of planer (pancake) or cylindrical type capacitor assisted edge resonant soft switching PWM series load working coil with electromagnetic eddy current based heated resonant high frequency inverter with two auxiliary edge materials. Consumer IH appliances operating at high resonant lossless inductor snubbers is proposed for small frequency ranges from 20 kHz to several MHz need a cost consumer induction heating appliances. The operation principle of this high frequency inverter is described using the switching effective product, high efficiency and high power density of mode equivalent circuits. This newly developed multi resonant high frequency inverters. Among various types of the high high frequency inverter using trench gate lGBTs can regulate its frequency inverter topologies, there are full bridge, half high frequency output AC power under a principle of constant bridge, single-ended push-pull (SEPP), centre tap push-pull frequency edge-resonant soft switching commutation by and boost-half bridge circuit configurations, in which voltage asymmetrical PWM control scheme. The high frequency power source type lossless snubber inductor assisted zero current regulation and actual power conversion efficiency characteristics soft switching (ZCS) SEPP series load resonant topologies, of consumer brand-new IH products that use the proposed soft voltage source type zero voltage soft switching (ZVS) SEPP switching PWM series load resonant high frequency inverter are resonant inverter and voltage source ZVZCS-SEEP multi evaluated. The practical effectiveness and operating resonant inverter topologies [4]-[8]. These high frequency soft performances of the newly proposed soft switching inverter are song inverter s have The high f soft discussed as compared with the conventional soft switching high switching inverterS have the advantages of simple frequency inverters based on simulation and experimental results configuration, high efficiency, low cost and wide soft from an application point of view.
The Journal of Symbolic Logic, 2008
We give a novel application of algebraic logic to first order logic. A new, flexible construction... more We give a novel application of algebraic logic to first order logic. A new, flexible construction is presented for representable but not completely representable atomic relation and cylindric algebras of dimension n (for finite n > 2) with the additional property that they are one-generated and the set of all n by n atomic matrices forms a cylindric basis. We use this construction to show that the classical Henkin-Orey omitting types theorem fails for the finite variable fragments of first order logic as long as the number of variables available is > 2 and we have a binary relation symbol in our language. We also prove a stronger result to the effect that there is no finite upper bound for the extra variables needed in the witness formulas. This result further emphasizes the ongoing interplay between algebraic logic and first order logic.
Bulletin of Symbolic Logic, 2005
On Complete Representations of Reducts of Polyadic Algebras
Studia Logica, 2008
Abstract Following research initiated by Tarski, Craig and Németi, and futher pursued by Sain and... more Abstract Following research initiated by Tarski, Craig and Németi, and futher pursued by Sain and others, we show that for certain subsets G of ω ω, atomic countable G polyadic algebras are completely representable. G polyadic algebras are obtained by restricting ...