7,198 research outputs found
The Lord\u27s Anointed: Covenantal Kingship in Psalm 2 and Acts 4
This study examines the title âChristâ as applied to Jesus in Acts 4:25-27. âChristâ or âAnointed Oneâ here is directly connected to Psalm 2:1-2, and ultimately derives from the royal anointing ceremony of Israel. That ceremony symbolizes a commitment by God to the monarch which is made most specific in the Davidic covenant. The Gospel of Luke uses the title âChristâ to connect these Davidic themes to Jesus. In Acts 4:25-27, âChristâ continues to signify Israelâs king backed by the Davidic covenant. The apostlesâ reading of Psalm 2 provides a foundation for understanding their own recent persecution and for their hope that the opponents of the King they representâlike those in Psalm 2âwill not prevail
In what sense can instruments and bodies be said to form spaces?
My recent work is an exploration of the physical and conceptual mechanisms that interface people with instruments. Central to this investigation is a conception of the performer/instrument assemblage as a symbiosis of two parallel and interdependent systems: one â the performer â moves through space established by the other â the instrument. Each system possesses its own intrinsic properties and characteristics; each possesses capacities to affect and be affected by one another. The music emanates from this contiguous interaction.
Instrument surface is understood as a compositional resource itself, a topological façade, defined by ordinal distances, that guides gestures along its contours. Within these fluctuating constellations of spatial coordinates, I consider all the relevant ways a body can move, and establish some general combinatory rules that inform the convergence of forces within the body. The traditional subjects of compositional contemplation such as form, duration, dynamic, etc. are not attributing features to the work per se but emerge as results from spatiotemporal relations of (bodily) movementâs correspondence with
(instrumental) surface and mechanism.
This liberation of movement is understood as a liberation of timbre, and the inherent indeterminacy of this relationship is embraced. As such, I would hypothesize that sound is, to an extent, freed from the subtractive tendencies of perception that might otherwise subvert it into generalized typological categories. Once liberated from the imagination, sound can bypass the brain and directly engage the nervous system
Classification of the maximal subalgebras of exceptional Lie algebras over fields of good characteristic
Let be an exceptional simple algebraic group over an algebraically closed
field and suppose that the characteristic of is a good prime for
. In this paper we classify the maximal Lie subalgebras of
the Lie algebra . Specifically, we show that one of
the following holds: for some maximal connected
subgroup of , or is a maximal Witt subalgebra of
, or is a maximal \it{\mbox{exotic semidirect
product}}. The conjugacy classes of maximal connected subgroups of G are known
thanks to the work of Seitz, Testerman and Liebeck--Seitz. All maximal Witt
subalgebras of are -conjugate and they occur when is not
of type and coincides with the Coxeter number of . We show
that there are two conjugacy classes of maximal exotic semidirect products in
, one in characteristic and one in characteristic , and
both occur when is a group of type .Comment: This version is accepted for publication in Journal of the American
Mathematical Society; 40 page
Rigid orbits and sheets in reductive Lie algebras over fields of prime characteristic
Let be a simple simply-connected algebraic group over an algebraically
closed field of characteristic with . We
discuss various properties of nilpotent orbits in , which have
previously only been considered over . Using a combination of
theoretical and computational methods, we extend to positive characteristic
various calculations of de Graaf with nilpotent orbits in exceptional Lie
algebras. In particular, we classify those orbits which are reachable, those
which satisfy a certain related condition due to Panyushev, and determine the
codimension in the centraliser of its the derived subalgebra
. Some of these calculations are used to show
that the list of rigid nilpotent orbits in , the classification
of sheets of and the distribution of the nilpotent orbits
amongst them are independent of good characteristic, remaining the same as in
the characteristic zero case. We also give a comprehensive account of the
theory of sheets in reductive Lie algebras over algebraically closed fields of
good characteristic.Comment: revised version, many typos corrected, 25 page
The collapse of cooperation in evolving games
Game theory provides a quantitative framework for analyzing the behavior of
rational agents. The Iterated Prisoner's Dilemma in particular has become a
standard model for studying cooperation and cheating, with cooperation often
emerging as a robust outcome in evolving populations. Here we extend
evolutionary game theory by allowing players' strategies as well as their
payoffs to evolve in response to selection on heritable mutations. In nature,
many organisms engage in mutually beneficial interactions, and individuals may
seek to change the ratio of risk to reward for cooperation by altering the
resources they commit to cooperative interactions. To study this, we construct
a general framework for the co-evolution of strategies and payoffs in arbitrary
iterated games. We show that, as payoffs evolve, a trade-off between the
benefits and costs of cooperation precipitates a dramatic loss of cooperation
under the Iterated Prisoner's Dilemma; and eventually to evolution away from
the Prisoner's Dilemma altogether. The collapse of cooperation is so extreme
that the average payoff in a population may decline, even as the potential
payoff for mutual cooperation increases. Our work offers a new perspective on
the Prisoner's Dilemma and its predictions for cooperation in natural
populations; and it provides a general framework to understand the co-evolution
of strategies and payoffs in iterated interactions.Comment: 33 pages, 13 figure
Small games and long memories promote cooperation
Complex social behaviors lie at the heart of many of the challenges facing
evolutionary biology, sociology, economics, and beyond. For evolutionary
biologists in particular the question is often how such behaviors can arise
\textit{de novo} in a simple evolving system. How can group behaviors such as
collective action, or decision making that accounts for memories of past
experience, emerge and persist? Evolutionary game theory provides a framework
for formalizing these questions and admitting them to rigorous study. Here we
develop such a framework to study the evolution of sustained collective action
in multi-player public-goods games, in which players have arbitrarily long
memories of prior rounds of play and can react to their experience in an
arbitrary way. To study this problem we construct a coordinate system for
memory- strategies in iterated -player games that permits us to
characterize all the cooperative strategies that resist invasion by any mutant
strategy, and thus stabilize cooperative behavior. We show that while larger
games inevitably make cooperation harder to evolve, there nevertheless always
exists a positive volume of strategies that stabilize cooperation provided the
population size is large enough. We also show that, when games are small,
longer-memory strategies make cooperation easier to evolve, by increasing the
number of ways to stabilize cooperation. Finally we explore the co-evolution of
behavior and memory capacity, and we find that longer-memory strategies tend to
evolve in small games, which in turn drives the evolution of cooperation even
when the benefits for cooperation are low
The evolution of complex gene regulation by low specificity binding sites
Transcription factor binding sites vary in their specificity, both within and
between species. Binding specificity has a strong impact on the evolution of
gene expression, because it determines how easily regulatory interactions are
gained and lost. Nevertheless, we have a relatively poor understanding of what
evolutionary forces determine the specificity of binding sites. Here we address
this question by studying regulatory modules composed of multiple binding
sites. Using a population-genetic model, we show that more complex regulatory
modules, composed of a greater number of binding sites, must employ binding
sites that are individually less specific, compared to less complex regulatory
modules. This effect is extremely general, and it hold regardless of the
regulatory logic of a module. We attribute this phenomenon to the inability of
stabilising selection to maintain highly specific sites in large regulatory
modules. Our analysis helps to explain broad empirical trends in the yeast
regulatory network: those genes with a greater number of transcriptional
regulators feature by less specific binding sites, and there is less variance
in their specificity, compared to genes with fewer regulators. Likewise, our
results also help to explain the well-known trend towards lower specificity in
the transcription factor binding sites of higher eukaryotes, which perform
complex regulatory tasks, compared to prokaryotes
Evolutionary consequences of behavioral diversity
Iterated games provide a framework to describe social interactions among
groups of individuals. Recent work stimulated by the discovery of
"zero-determinant" strategies has rapidly expanded our ability to analyze such
interactions. This body of work has primarily focused on games in which players
face a simple binary choice, to "cooperate" or "defect". Real individuals,
however, often exhibit behavioral diversity, varying their input to a social
interaction both qualitatively and quantitatively. Here we explore how access
to a greater diversity of behavioral choices impacts the evolution of social
dynamics in finite populations. We show that, in public goods games, some
two-choice strategies can nonetheless resist invasion by all possible
multi-choice invaders, even while engaging in relatively little punishment. We
also show that access to greater behavioral choice results in more "rugged "
fitness landscapes, with populations able to stabilize cooperation at multiple
levels of investment, such that choice facilitates cooperation when returns on
investments are low, but hinders cooperation when returns on investments are
high. Finally, we analyze iterated rock-paper-scissors games, whose
non-transitive payoff structure means unilateral control is difficult and
zero-determinant strategies do not exist in general. Despite this, we find that
a large portion of multi-choice strategies can invade and resist invasion by
strategies that lack behavioral diversity -- so that even well-mixed
populations will tend to evolve behavioral diversity.Comment: 26 pages, 4 figure
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