A two component model of negative U centers coupled with the Fermi sea of itinerant fermions is discussed in connection with high-temperature superconductivity of cuprates, and superfluidity of atomic fermions. We examine the phase transition and the condensed state of this boson-fermion model...

With the superconducting cuprates in mind, a set of unitary transformations was used to decouple electrons and phonons in the strong-coupling limit. While phonons remain almost unrenormalised, electrons are transformed into itinerent singlet and triplet bipolarons and thermally excited polarons....

Magnetoresistance (MR) of Bi-2212 single crystals with <InlineEquation ID="Equ5"> <EquationSource Format="TEX">$T_{c} \approx 87-92$</EquationSource> </InlineEquation> K is studied in pulsed magnetic fields up to 50 T along the c-axis in a wide temperature range. The negative out-of-plane and the positive in-plane MRs are measured in the normal state. Both MRs have similar...</equationsource></inlineequation>

The question of the economic role of the state budget in social reproduction under socialism is not yet adequately worked out. Yet it is of great importance for the theory of Soviet finance, as well as for financial practice. Therefore one has to stress the importance and timeliness of the...

<title>Abstract</title> <italic>This work models outsourcing under oligopolistic competition with nonlinear costs. I show that in a covered market, if each firm's marginal cost before outsourcing is lower than the industry's average cost, outsourcing leads to increased prices and decreased consumer welfare. Joint...</italic>

We show that a monopolist's problem of optimal advance selling strategy can be mathematically transformed into a problem of optimal bundling strategy if four conditions hold: i. consumers and the firm agree on the probability of the states occurring, ii. the firm pre-commits to the spot prices...

The economics literature generally considers products as points in some characteristics space. Starting with Hotelling, this served as a convenient assumption, yet with more products being flexible or self-customizable to some degree it makes sense to think that products have positive measure. I...

"The economics literature generally considers products as points in some characteristics space. With more products being flexible or self-customizable to some degree, it makes sense to model products with positive measure. I develop a model of firms which can offer interval-long "fat" products...

I examine interconnection decisions of differentiated firms. I find that previous results that firms never interconnect enough do not hold. In a Hotelling model consumers may suffer from interconnection, and firms may interconnect when it is not socially optimal. The firms interconnect too much...

We examine a model of a monopolist selling to two segments of consumers with different preferences for quality. We show that if the firm is unable to price discriminate between the segments, then there is less investment in quality. We find that both consumer segments, and society overall, may...