The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Saharon Shelah - One of the best experts on this subject based on the ideXlab platform.
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The cofinality of the symmetric group and the cofinality of ultrapowers
Israel Journal of Mathematics, 2021Co-Authors: Heike Mildenberger, Saharon ShelahAbstract:We prove that $$\mathfrak{mcf}$$ m c f and $$\mathfrak{mcf}$$ m c f are both Consistent Relative to ZFC. This answers a question by Banakh, Repovš and Zdomskyy and a question from [ MS11 ].
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A small ultrafilter number at smaller cardinals
Archive for Mathematical Logic, 2020Co-Authors: Dilip Raghavan, Saharon ShelahAbstract:It is proved to be Consistent Relative to a measurable cardinal that there is a uniform ultrafilter on the real numbers which is generated by fewer than the maximum possible number of sets. It is also shown to be Consistent Relative to a supercompact cardinal that there is a uniform ultrafilter on $${\aleph }_{\omega +1}$$ ℵ ω + 1 which is generated by fewer than $${2}^{{\aleph }_{\omega +1}}$$ 2 ℵ ω + 1 sets.
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transcendence bases well orderings of the reals and the axiom of choice
arXiv: Logic, 2019Co-Authors: Haim Horowitz, Saharon ShelahAbstract:We prove that $ZF+DC+"$there exists a transcendence basis for the reals$"+"$there is no well-ordering of the reals$"$ is Consistent Relative to $ZFC$. This answers a question of Larson and Zapletal.
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SPECIALIZING ARONSZAJN TREES AND PRESERVING SOME WEAK DIAMONDS
Journal of Applied Analysis, 2009Co-Authors: Heike Mildenberger, Saharon ShelahAbstract:We show that}( ;N;2) together with CH and \all Aron- szajn trees are special" is Consistent Relative to ZFC. The weak diamond for the covering relation of Lebesgue null sets was the only weak dia- mond in the Cicho n diagramme for relations whose consistency together with \all Aronszajn trees are special" was not yet settled. Our forcing proof gives also new proofs to the known consistencies of several other weak diamonds stemming from the Cicho n diagramme together with \all Aronszajn trees are special" and CH. The main part of our work is an application (15, Chapter V,xx 1{7) for a special completeness system, such that we have a genericity game. Thus we show new preservation properties of the known forcings.
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Winning the pressing down game but not Banach Mazur
Journal of Symbolic Logic, 2007Co-Authors: Jakob Kellner, Matti Pauna, Saharon ShelahAbstract:Let $S$ be the set of those $\alpha\in\omega_2$ that have cofinality $\omega_1$. It is Consistent Relative to a measurable that the nonempty player wins the pressing down game of length $\omega_1$, but not the Banach Mazur game of length $\omega+1$ (both games starting with $S$).
Bert R. Mead - One of the best experts on this subject based on the ideXlab platform.
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ocular estimates of understory vegetation structure in a closed picea glauca betula papyrifera forest
Journal of Vegetation Science, 2000Co-Authors: W.s. Willem, Bert R. MeadAbstract:. Horizontal/vertical profiling is a method used to assess vegetation space occupancy. This study investigated consistency and repeatability of measurements made on plots designed to describe forest understory vegetation structure. 20 circular, 100-m2 plots were measured by six independent observers, three times during the summer of 1997. The plots, located in south-central Alaska, were established in a closed Picea glauca (white spruce)/Betula papyrifera (paper birch) forest. Consistency and repeatability of measurements were evaluated by examining components of variance. Response variables were absolute and Relative canopy cover. Results indicate that observers were not Consistent Relative to each other estimating vegetative cover from one plot to the next and from one measurement period to the next, making measurements unrepeatable.
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Ocular estimates of understory vegetation structure in a closed Picea glauca/Betula papyrifera forest
Journal of Vegetation Science, 2000Co-Authors: Hees, W.s. Willem, Bert R. MeadAbstract:. Horizontal/vertical profiling is a method used to assess vegetation space occupancy. This study investigated consistency and repeatability of measurements made on plots designed to describe forest understory vegetation structure. 20 circular, 100-m2 plots were measured by six independent observers, three times during the summer of 1997. The plots, located in south-central Alaska, were established in a closed Picea glauca (white spruce)/Betula papyrifera (paper birch) forest. Consistency and repeatability of measurements were evaluated by examining components of variance. Response variables were absolute and Relative canopy cover. Results indicate that observers were not Consistent Relative to each other estimating vegetative cover from one plot to the next and from one measurement period to the next, making measurements unrepeatable.
Heike Mildenberger - One of the best experts on this subject based on the ideXlab platform.
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The cofinality of the symmetric group and the cofinality of ultrapowers
Israel Journal of Mathematics, 2021Co-Authors: Heike Mildenberger, Saharon ShelahAbstract:We prove that $$\mathfrak{mcf}$$ m c f and $$\mathfrak{mcf}$$ m c f are both Consistent Relative to ZFC. This answers a question by Banakh, Repovš and Zdomskyy and a question from [ MS11 ].
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Finding generic filters by playing games
Archive for Mathematical Logic, 2009Co-Authors: Heike MildenbergerAbstract:We give some restrictions for the search for a model of the club principle with no Souslin trees. We show that \({\diamondsuit(2^\omega, [\omega]^\omega}\), is almost constant on) together with CH and “all Aronszajn trees are special” is Consistent Relative to ZFC. This implies the analogous result for a double weakening of the club principle.
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Creatures on ω1 and weak diamonds
The Journal of Symbolic Logic, 2009Co-Authors: Heike MildenbergerAbstract:AbstractWe specialise Aronszajn trees by an ωω-bounding forcing that adds reals. We work with creature forcings on uncountable spaces.As an application of these notions of forcing, we answer a question of Moore, Hrušák and Džamonja whether implies the existence of a Souslin tree in a negative way by showing that “ and every Aronszajn tree is special” is Consistent Relative to ZFC.
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SPECIALIZING ARONSZAJN TREES AND PRESERVING SOME WEAK DIAMONDS
Journal of Applied Analysis, 2009Co-Authors: Heike Mildenberger, Saharon ShelahAbstract:We show that}( ;N;2) together with CH and \all Aron- szajn trees are special" is Consistent Relative to ZFC. The weak diamond for the covering relation of Lebesgue null sets was the only weak dia- mond in the Cicho n diagramme for relations whose consistency together with \all Aronszajn trees are special" was not yet settled. Our forcing proof gives also new proofs to the known consistencies of several other weak diamonds stemming from the Cicho n diagramme together with \all Aronszajn trees are special" and CH. The main part of our work is an application (15, Chapter V,xx 1{7) for a special completeness system, such that we have a genericity game. Thus we show new preservation properties of the known forcings.
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Cardinal characteristics for Menger-bounded subgroups
Topology and its Applications, 2008Co-Authors: Heike MildenbergerAbstract:Abstract Machura, Shelah and Tsaban showed in [M. Machura, S. Shelah, B. Tsaban, Squares of Menger-bounded groups, Trans. Amer. Math. Soc., in press, http://arxiv.org/pdf/math.GN/0611353 , 2007] that under the condition, that a Relative d ′ ( P ) of the dominating number is at least d , there are subgroups of the Baer–Specker group whose kth power is Menger-bounded and whose ( k + 1 ) st power is not. We show that the sufficient condition implies r ⩾ d and indeed can be replaced by r ⩾ d . This result includes an affirmative answer to a question by Tsaban on a possibly weaker still sufficient condition. We show that it is Consistent Relative to ZFC that g ⩽ r d and there are subgroups of the Baer–Specker group whose kth power is Menger-bounded and whose ( k + 1 ) st power is not.
W.s. Willem - One of the best experts on this subject based on the ideXlab platform.
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ocular estimates of understory vegetation structure in a closed picea glauca betula papyrifera forest
Journal of Vegetation Science, 2000Co-Authors: W.s. Willem, Bert R. MeadAbstract:. Horizontal/vertical profiling is a method used to assess vegetation space occupancy. This study investigated consistency and repeatability of measurements made on plots designed to describe forest understory vegetation structure. 20 circular, 100-m2 plots were measured by six independent observers, three times during the summer of 1997. The plots, located in south-central Alaska, were established in a closed Picea glauca (white spruce)/Betula papyrifera (paper birch) forest. Consistency and repeatability of measurements were evaluated by examining components of variance. Response variables were absolute and Relative canopy cover. Results indicate that observers were not Consistent Relative to each other estimating vegetative cover from one plot to the next and from one measurement period to the next, making measurements unrepeatable.
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Ocular estimates of understory vegetation structure in a closed Picea glauca/Betula papyrifera forest
Journal of Vegetation Science, 2000Co-Authors: Hees, W.s. Willem, Bert R. MeadAbstract:. Horizontal/vertical profiling is a method used to assess vegetation space occupancy. This study investigated consistency and repeatability of measurements made on plots designed to describe forest understory vegetation structure. 20 circular, 100-m2 plots were measured by six independent observers, three times during the summer of 1997. The plots, located in south-central Alaska, were established in a closed Picea glauca (white spruce)/Betula papyrifera (paper birch) forest. Consistency and repeatability of measurements were evaluated by examining components of variance. Response variables were absolute and Relative canopy cover. Results indicate that observers were not Consistent Relative to each other estimating vegetative cover from one plot to the next and from one measurement period to the next, making measurements unrepeatable.
G.j. Boland - One of the best experts on this subject based on the ideXlab platform.
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A simple and inexpensive control of Relative humidity in a flow-through environmental chamber
Environmental and Experimental Botany, 1995Co-Authors: D.j. Hannusch, T.d.w. James, T. J. Gillespie, G.j. BolandAbstract:Abstract A simple, Relatively inexpensive, and effective method for the control of Relative humidity in an environmental chamber was developed and evaluated. Relative humidity was maintained at 90% ± 0.4% and 95.2% ± 0.5% through the use of a micrologger-controlled ultrasonic mister that cycled between Relatively narrow set points. To maintain Consistent Relative humidity, misters were activated at approximately 5- and 3-min intervals at 90% and 95% Relative humidity, respectively. Air temperatures of 20–28°C were maintained at ±0.5°C by regulation of growth room controls. This environmental chamber has considerable utility for investigations of the influence of Relative humidity and water potential on plants and plant-associated microorganisms.