Harmonic morphisms from the Grassmannians and their non-compact duals

In this paper we give a unified framework for the construction of complex valued harmonic morphisms from the real, complex and quaternionic Grassmannians and their non-compact duals. This gives a positive answer to the corresponding open existence problem in the real and quaternionic cases.Comment: 21 page

Harmonic morphisms from four dimensional Lie groups

We consider four dimensional Lie groups with left-invariant Riemannian metrics. For such groups we classify left-invariant conformal foliations with minimal leaves of codimension two. These foliations produce local complex-valued harmonic morphisms

Using Narratives, Humor, and Social Navigation: An Inspection of two systems

PERSON

Complete minimal submanifolds of compact Lie groups

We give a new method for manufacturing complete minimal submanifolds of compact Lie groups and their homogeneous quotient spaces. For this we make use of harmonic morphisms and basic representation theory of Lie groups. We then apply our method to construct many examples of compact minimal submanifolds of the special unitary groups

Social positioning: Designing the Seams between Social, Physical and Digital Space

Mobile settings are not only physically and digitally mediated; they are also inhabited by people - a social space. We argue that careful design exposing the connections, gaps, overlays and mismatches within and between physical, digital and social space allow for a better understanding and thereby mastering of the resulting combined space. Two concepts are explored in MobiTip, a social mobile service for exchanging opinions among peers: intramedia seams concerning network coverage and position technology, and intermedia seams between digitally transmitted tips and the physical, social context surrounding the user. We introduce social positioning as an alternative and complement to the current strive for seamless connectedness and exact positioning in physical space

Design Principals of Social Navigation

8th Delos Workshop on "User Interfaces for Digital Libraries" (on 21 October it will be held in conjuction with the 4th ERCIM Workshop on "User Interfaces for All"), SICS, Kista, Sweden, 21-23 October 1998PERSON