A variational approach to the Yau-Tian-Donaldson conjecture

We give a variational proof of a version of the Yau-Tian-Donaldson conjecture for twisted K\"ahler-Einstein currents, and use this to express the greatest (twisted) Ricci lower bound in terms of a purely algebro-geometric stability threshold. Our approach does not involve the continuity method or Cheeger-Colding-Tian theory, and uses instead pluripotential theory and valuations. Along the way, we study the relationship between geodesic rays and non-Archimedean metrics.Comment: Added Appendix B on a valuative analysis of singularities of plurisubharmonic functions. Various other small changes and improvements. To appear in Journal of the AM

A diminishing population whose every cohort more than replaces itself

We observe that a dynamic population model can have period fertility that is always below replacement and cohort fertility that is always above replacement. We ask whether such a paradoxical population will get larger or smaller, and show that it must become smaller. Cohort replacement does not imply population replacement, and emphasizing fertility timing and cohort fertility ignores the issue of relative cohort size. The resolution of this apparent paradox reinforces the importance of the level of period fertility in demographic analysis.Bongaarts-Feeney adjusted fertility, cohort, cohort fertility, dynamic population model, fertility, fertility timing, period fertility

Estimating multistate transition rates from population distributions

The ability to estimate transition rates (or probabilities) from population distributions has many potential applications in demography. Iterative Proportional Fitting (IPF) has been used for such estimation, but lacks a meaningful behavioral, or demographic, foundation. Here a new approach, Relative State Attractiveness (RSA), is advanced. It assumes that states become more (or less) attractive, and that rates respond accordingly. The RSA estimation procedure is developed and applied to model and actual data where the underlying rates are known. Results show that RSA provides accurate estimates under a wide range of conditions, usually yielding values similar to those produced by IPF. Both methods are then applied to U.S. data to provide new estimates of interregional migration between the years 1980 and 1990.entropy, estimation techniques, iterative proportional fitting, multistate models

Transmitting qubits through relativistic fields

Wireless communication derives its power from the simultaneous emission of signals in multiple directions. However, in the context of quantum communication, this phenomenon must be reconciled carefully with the no-cloning principle. In this context, we here study how wireless communication of quantum information can be realized via relativistic fields. To this end, we extend existing frameworks to allow for a non-perturbative description of, e.g., quantum state transfer. We consider, in particular, the case of 1+1 spacetime dimensions, which already allows a number of interesting scenarios, pointing to, for example, new methods for tasks similar to quantum secret sharing.Comment: v2: published versio

An assessment of sourcing strategies in the apparel industry

Purpose – The purpose of this paper is to empirically identify different types of sourcing strategies applied in the apparel industry, and to explain how various sourcing strategies are related to the apparel firm’s characteristics, prerequisites and supplier performance. Design/methodology/approach – This paper is based on a survey that was sent out to Swedish apparel firms. Commonly applied sourcing strategies, in terms of supply markets and supply channels, are first derived using cluster analysis. These strategies are then linked to relevant firm characteristics, prerequisites and supplier performance measures, where significant differences between groups of firms applying various sourcing strategies are targeted. Findings – Five commonly applied sourcing strategies are identified. Further, several significant differences – with respect to product issues, organizational issues and supplier performance – are found between the firm groups. Research limitations/implications – Several future research areas in conjunction with this study can be derived by widening or changing the scope. For instance, other industries as well as apparel industries in other countries can be targeted and thus provide valuable comparisons. Practical implications – Assessing the contextual appropriateness of sourcing strategies provides a strategic sourcing benchmark for firms across industries. Notably, apparel firms’ experience in exploiting low-cost supply markets may provide valuable insights for firms that just recently have recognized the potential of these markets. Originality/value – This paper provides a contextual understanding of how various sourcing strategies are utilized in the Swedish apparel industry, and thereby contributes to the general conception of sourcing strategies

Mirroring to Build Trust in Digital Assistants

We describe experiments towards building a conversational digital assistant that considers the preferred conversational style of the user. In particular, these experiments are designed to measure whether users prefer and trust an assistant whose conversational style matches their own. To this end we conducted a user study where subjects interacted with a digital assistant that responded in a way that either matched their conversational style, or did not. Using self-reported personality attributes and subjects' feedback on the interactions, we built models that can reliably predict a user's preferred conversational style.Comment: Preprin