Robust Stackelberg Equilibria in Extensive-Form Games and Extension to Limited Lookahead

Stackelberg equilibria have become increasingly important as a solution concept in computational game theory, largely inspired by practical problems such as security settings. In practice, however, there is typically uncertainty regarding the model about the opponent. This paper is, to our knowledge, the first to investigate Stackelberg equilibria under uncertainty in extensive-form games, one of the broadest classes of game. We introduce robust Stackelberg equilibria, where the uncertainty is about the opponent's payoffs, as well as ones where the opponent has limited lookahead and the uncertainty is about the opponent's node evaluation function. We develop a new mixed-integer program for the deterministic limited-lookahead setting. We then extend the program to the robust setting for Stackelberg equilibrium under unlimited and under limited lookahead by the opponent. We show that for the specific case of interval uncertainty about the opponent's payoffs (or about the opponent's node evaluations in the case of limited lookahead), robust Stackelberg equilibria can be computed with a mixed-integer program that is of the same asymptotic size as that for the deterministic setting.Comment: Published at AAAI1

Pengaruh Sosialisasi Perpajakan, Pengetahuan Perpajakan, dan Kualitas Pelayanan terhadap Kepatuhan Wajib Pajak dengan Kesadaran Wajib Pajak sebagai Variabel Intervening (Studi pada Kantor Pelayanan Pajak Pratama Pekanbaru Senapelan)

The purpose of this research are to analyze the influence of taxpayer socialization, taxpayer knowledge, and quality of service to taxpayer compliance, directly or indirectly, by usingtaxpayer awareness as an intervening variable.The sample of this research from of 100 correspondences who are as taxpayers listed in KPP Pratama Pekanbaru Senapelan.The method of sampling using convenience sampling. The data were analysed using the path analysis with SPSS version 19.0. The results of the research showed that the tax socialization did have effect to the tax awareness. Secondly, the tax knowledge did have effect to the tax awareness. Third, quality of service did have effect to the tax awareness.Fourth, the tax socialization did have effect tothe tax compliance. Fifth, the tax knowledge did have effect tothe tax compliance. Sixth, quality of service did have noteffect tothe tax compliance. Seventh, the tax awareness did have effect tothe tax compliance. Eighth, the tax awareness incapable as an intervening variable tax socialization to tax compliance. Ninth, the tax awareness incapable as an intervening variable tax knowledge to tax compliance. Tenth, the tax awareness able as an intervening variable quality of service to tax compliance

Screening and preparation of cocrystals: A comparative study of mechanochemistry vs slurry methods

Cocrystals of biologically active molecular compounds have potential utility in drug products thanks to their effect upon physicochemical properties such as aqueous solubility. The fact that control of cocrystallization can be more challenging than crystallization of single component crystals means that systematic studies that address the methodology of cocrystal screening, production, and purification are a topical subject. We previously reported a comparison of slow evaporation vs mechanochemistry for a library of 25 molecular cocrystals. Herein, we compare the previously reported mechanochemistry results (solvent-drop grinding (SDG) with eight solvents) with new results obtained from slurrying in five preferred solvents using the same library of 25 cocrystals. Overall, both methods were found to be effective with slurrying and SDG being 94 and 78.5% successful, respectively. Importantly, 96% of the cocrystals formed via slurrying were observed to be free of starting materials (coformers) according to powder X-ray diffraction (PXRD), whereas this was the case for only 72% of the cocrystals prepared by SDG. Slurrying therefore compared favorably with mechanochemistry, which tends to leave small amounts of unreacted coformer(s) as byproducts, and solution crystallization, which often affords crystals of the least soluble coformer because it can be difficult to control the saturation of three or more solids. Perhaps the most interesting and surprising result of this study was that water slurrying proved to be highly effective, even for low-solubility coformers. Indeed, water slurrying was found to be effective for 21 of the 25 cocrystals studie

Spiers Memorial Lecture: Coordination networks that switch between nonporous and porous structures: an emerging class of soft porous crystals

Coordination networks (CNs) are a class of (usually) crystalline solids typically comprised of metal ions or cluster nodes linked into 2 or 3 dimensions by organic and/or inorganic linker ligands. Whereas CNs tend to exhibit rigid structures and permanent porosity as exemplified by most metal–organic frameworks, MOFs, there exists a small but growing class of CNs that can undergo extreme, reversible structural transformation(s) when exposed to gases, vapours or liquids. These “soft” or “stimuli-responsive” CNs were introduced two decades ago and are attracting increasing attention thanks to two features: the amenability of CNs to design from first principles, thereby enabling crystal engineering of families of related CNs; and the potential utility of soft CNs for adsorptive storage and separation. A small but growing subset of soft CNs exhibit reversible phase transformations between nonporous (closed) and porous (open) structures. These “switching CNs” are distinguished by stepped sorption isotherms coincident with phase transformation and, perhaps counterintuitively, they can exhibit benchmark properties with respect to working capacity (storage) and selectivity (separation). This review addresses fundamental and applied aspects of switching CNs through surveying their sorption properties, analysing the structural transformations that enable switching, discussing structure–function relationships and presenting design principles for crystal engineering of the next generation of switching CNs

Water Vapor Sorption in Hybrid Pillared Square Grid Materials

We report water vapor sorption studies on four primitive cubic, <b>pcu</b>, pillared square grid materials: <b>SIFSIX-1-Cu</b>, <b>SIFSIX-2-Cu-i</b>, <b>SIFSIX-3-Ni</b>, and <b>SIFSIX-14-Cu-i</b>. <b>SIFSIX-1-Cu</b>, <b>SIFSIX-3-Ni</b>, and <b>SIFSIX-14-Cu-i</b> were observed to exhibit negative water vapor adsorption at ca. 40–50% relative humidity (RH). The negative adsorption is attributed to a water-induced phase transformation from a porous <b>pcu</b> topology to nonporous <b>sql</b> and <b>sql-c*</b> topologies. Whereas the phase transformation of <b>SIFSIX-1-Cu</b> was found to be irreversible, <b>SIFSIX-3-Ni</b> could be regenerated by heating and can therefore be recycled. In contrast, <b>SIFSIX-2-Cu-i</b>, which is isostructural with <b>SIFSIX-14-Cu-i</b>, exhibited a type V isotherm and no phase change. <b>SIFSIX-2-Cu-i</b> was observed to retain both structure and gas sorption properties after prolonged exposure to heat and humidity. The hydrolytic stability of <b>SIFSIX-2-Cu-i</b> in comparison to its structural counterparts is attributed to structural features and therefore offers insight into the design of hydrolytically stable porous materials

Structural Insight into Guest Binding Sites in a Porous Homochiral Metal–Organic Material

An enantiomeric pair of chiral metal–organic materials (CMOMs) based upon mandelate (man) and 4,4′-bipyridine (bpy) ligands, [Co₂(<i>S</i>-man)₂(bpy)₃]­(NO₃)₂·guest (<b>1S·guest</b>) and [Co₂(<i>R</i>-man)₂(bpy)₃]­(NO₃)₂·guest (<b>1R·guest</b>), have been prepared. The cationic frameworks exhibit one-dimensional chiral channels with dimensions of 8.0 Å × 8.0 Å. The pore chemistry is such that chiral surfaces lined with nitrate anions and phenyl groups create multiple binding sites for guest and/or solvent molecules. The performance of <b>1S</b> and <b>1R</b> with respect to resolution of racemic mixtures of 1-phenyl-1-propanol (PP) was studied by varying time, temperature, and the use of additives. Selectivity toward PP was determined by chiral HPLC with <i>ee</i> values of up to 60%. The binding sites and host–guest interactions were investigated through single-crystal X-ray structural analyses of guest-exchanged <b>1S</b> and <b>1R</b>. Crystallographically observed structural changes (e.g., the absolute configurations of the three PP binding sites switch from <i>R</i>, <i>R</i>, and <i>S</i> to <i>R</i>, <i>R</i>, and <i>R</i>/<i>S</i>) correlate with experimentally observed <i>ee</i> values of 33% and 60% for variants of <b>1S</b> that contain PP and different solvent molecules, <b>1S·PPex</b> and <b>1S·PPex′</b>, respectively. The fact that manipulation of guest solvent molecules, which in effect serve as cofactors, can modify chiral sites and increase enantioselectivity is likely to aid in the design of more effective CMOMs and processes for chiral separations

Three Porphyrin-Encapsulating Metal–Organic Materials with Ordered Metalloporphyrin Moieties

1,3,5-benzenetricarboxylate, biphenyl-3,4′,5-tricarboxylate, and [1,1′:3′,1″-terphenyl]-4,4″,5′-tricarboxylate react with Cd­(II) cations in the presence of meso-tetra­(<i>N</i>-methyl-4-pyridyl) porphine cations to afford three metalloporphyrin-encapsulating metal–organic materials, <b>porph@MOM-11</b>, <b>-12</b> and <b>-13</b>, respectively. The metalloporphyrin moieties are ordered within channels and closely fit hexagonal or rectangular cavities, thereby facilitating a better understanding of the structure-directing effect that can be promoted by metalloporphyrins. <b>Porph@MOM-12</b> is noteworthy because it exhibits two distinct types of hexagonal channels and it represents the first example of a net that exhibits <b>mzz</b> topology

Experiences of alien control in schizophrenia reflect a disorder in the central monitoring of action.

Twenty-three acute psychotic patients who were drug free at the time of testing performed a motor task designed to elicit many errors. Normal subjects and many of the psychotic patients were able to correct these errors in the absence of visual feedback. The ability to make such corrections depends on the subject knowing what response he has just made. Patients with experiences of alien control of their thoughts and actions who formed a subgroup of those classified as schizophrenic, were significantly less likely to make error corrections in the absence of visual feedback. This result is consistent with our previous suggestion (Frith, 1987) that these symptoms are a consequence of problems with the central monitoring of responses

Chloral Hydrate Polymorphs and Cocrystal Revisited: Solving Two Pharmaceutical Cold Cases

Chloral hydrate has the distinction of perhaps being the first reported example of a pharmaceutical compound to exhibit polymorphism (1877) and the first use of a pharmaceutical cocrystal in a drug product (Beta-Chlor, 1960s). Nevertheless, chloral hydrate represents a microcosm of contemporary issues in solid-state chemistry and its importance to pharmaceutical science. Ironically, the single crystal structures of the β-form of chloral hydrate and its pharmaceutical cocrystal with betaine have not yet been reported. In this contribution, the single crystal structures and physical properties of these crystal forms are reported for the first time. The previously termed “high temperature” β-form of chloral hydrate was obtained by melting the α-form of chloral hydrate and crystallizing from the melt. The α-form of chloral hydrate is comprised of diol–diol homodimers that further assemble into a sheet of six-membered rings. The β-form is sustained by head-to-tail OH···O hydrogen bonds that form a sheet built from two types of three- and five-membered rings. The diol–diol interactions that sustain these polymorphs are placed in context through a Cambridge Structural Database analysis. The chloral hydrate–betaine cocrystal (CHOBTN) was obtained by slow cooling from water, exhibits higher thermal stability than the chloral hydrate polymorphs, and is sustained by a previously known 2-point diol-carboxylate supramolecular heterosynthon that could be of general utility

Stepwise Transformation of the Molecular Building Blocks in a Porphyrin-Encapsulating Metal–Organic Material

When immersed in solutions containing Cu­(II) cations, the microporous metal–organic material <b>P11</b> ([Cd₄(BPT)₄]·[Cd­(C₄₄H₃₆N₈)­(S)]·[S], BPT = biphenyl-3,4′,5-tricarboxylate) undergoes a transformation of its [Cd₂(COO)₆]^2– molecular building blocks (MBBs) into novel tetranuclear [Cu₄X₂(COO)₆(S)₂] MBBs to form <b>P11-Cu</b>. The transformation occurs in single-crystal to single-crystal fashion, and its stepwise mechanism was studied by varying the Cd²⁺/Cu²⁺ ratio of the solution in which crystals of <b>P11</b> were immersed. <b>P11-16/1</b> (Cd in framework retained, Cd in encapsulated porphyrins exchanged) and other intermediate phases were thereby isolated and structurally characterized. <b>P11-16/1</b> and <b>P11-Cu</b> retain the microporosity of <b>P11</b>, and the relatively larger MBBs in <b>P11-Cu</b> permit a 20% unit cell expansion and afford a higher surface area and a larger pore size