6,604 research outputs found
Hype, skill and class : a comparative analysis of the politics of reforms in Andhra Pradesh, India
politics; economic reform; India;
Algebraic equivalence between certain models for superfluid--insulator transition
Algebraic contraction is proposed to realize mappings between models
Hamiltonians. This transformation contracts the algebra of the degrees of
freedom underlying the Hamiltonian. The rigorous mapping between the
anisotropic Heisenberg model, the Quantum Phase Model, and the Bose
Hubbard Model is established as the contractions of the algebra
underlying the dynamics of the Heisenberg model.Comment: 5 pages, revte
Reinventing the Dutch tax-benefit system; exploring the frontier of the equity-efficiency trade-off
European governments aim to raise labour supply, cut unemployment and, at the same time, maintain social cohesion. Yet, economists have stressed the trade-off between these objectives. This paper reviews the key policy insights from optimal tax theory to identify options for reform in the tax-benefit system that can potentially improve the equity-efficiency trade-off. Using a comprehensive applied general equilibrium model, we then explore whether reforms along these lines in the actual Dutch tax-benefit system will raise employment without sacrificing equality. The analysis reveals that selective tax relief for elastic secondary earners and low-skilled workers have this potential. A flat income tax structure possibly combined with a negative income tax worsens the equity-efficiency trade-off.
Constraint-Based Causal Discovery using Partial Ancestral Graphs in the presence of Cycles
While feedback loops are known to play important roles in many complex
systems, their existence is ignored in a large part of the causal discovery
literature, as systems are typically assumed to be acyclic from the outset.
When applying causal discovery algorithms designed for the acyclic setting on
data generated by a system that involves feedback, one would not expect to
obtain correct results. In this work, we show that---surprisingly---the output
of the Fast Causal Inference (FCI) algorithm is correct if it is applied to
observational data generated by a system that involves feedback. More
specifically, we prove that for observational data generated by a simple and
-faithful Structural Causal Model (SCM), FCI is sound and complete, and
can be used to consistently estimate (i) the presence and absence of causal
relations, (ii) the presence and absence of direct causal relations, (iii) the
absence of confounders, and (iv) the absence of specific cycles in the causal
graph of the SCM. We extend these results to constraint-based causal discovery
algorithms that exploit certain forms of background knowledge, including the
causally sufficient setting (e.g., the PC algorithm) and the Joint Causal
Inference setting (e.g., the FCI-JCI algorithm).Comment: Major revision. To appear in Proceedings of the 36 th Conference on
Uncertainty in Artificial Intelligence (UAI), PMLR volume 124, 202
Markov Properties for Graphical Models with Cycles and Latent Variables
We investigate probabilistic graphical models that allow for both cycles and
latent variables. For this we introduce directed graphs with hyperedges
(HEDGes), generalizing and combining both marginalized directed acyclic graphs
(mDAGs) that can model latent (dependent) variables, and directed mixed graphs
(DMGs) that can model cycles. We define and analyse several different Markov
properties that relate the graphical structure of a HEDG with a probability
distribution on a corresponding product space over the set of nodes, for
example factorization properties, structural equations properties,
ordered/local/global Markov properties, and marginal versions of these. The
various Markov properties for HEDGes are in general not equivalent to each
other when cycles or hyperedges are present, in contrast with the simpler case
of directed acyclic graphical (DAG) models (also known as Bayesian networks).
We show how the Markov properties for HEDGes - and thus the corresponding
graphical Markov models - are logically related to each other.Comment: 131 page
Constraint-based Causal Discovery for Non-Linear Structural Causal Models with Cycles and Latent Confounders
We address the problem of causal discovery from data, making use of the
recently proposed causal modeling framework of modular structural causal models
(mSCM) to handle cycles, latent confounders and non-linearities. We introduce
{\sigma}-connection graphs ({\sigma}-CG), a new class of mixed graphs
(containing undirected, bidirected and directed edges) with additional
structure, and extend the concept of {\sigma}-separation, the appropriate
generalization of the well-known notion of d-separation in this setting, to
apply to {\sigma}-CGs. We prove the closedness of {\sigma}-separation under
marginalisation and conditioning and exploit this to implement a test of
{\sigma}-separation on a {\sigma}-CG. This then leads us to the first causal
discovery algorithm that can handle non-linear functional relations, latent
confounders, cyclic causal relationships, and data from different (stochastic)
perfect interventions. As a proof of concept, we show on synthetic data how
well the algorithm recovers features of the causal graph of modular structural
causal models.Comment: Accepted for publication in Conference on Uncertainty in Artificial
Intelligence 201
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