Recoil

Recoil examines my personal experiences in recovering from a car accident. The word ‘recoil’ is used in two senses: to change speed and direction as a result of a collision; to shrink in fear. The work represents a labyrinth of memory, where the fragmented self confronts distorted realities and fearful illusions. Recoil builds upon the harmonic explorations of my string quartet Impacts and Fractures (1999): a ‘dominant seventh’ chord, partials 4-7 of the harmonic series, is tempered to the quarter-tone scale and elaborated to create a series of complex modes. These modes regulate all the melodic and harmonic material for both the soloist and the tape part. The tape part is derived entirely from the processed recording of an acoustic piano, and takes the role of a superinstrument that confronts, encompasses and absorbs the soloist. The work is a result of the extensive analysis and processing of melodic fragments, performed on the piano by myself, employing the recent IRCAM program ‘Audiosculpt’. These fragments are: transposed by microintervals to produce a harmonically rich chorus of arabesques; independently modified in pitch and tempo to realise rhythmically complex dialogues with the soloist; filtered and transposed to create a continuum of sounds ranging from a recognisable piano towards noise; greatly expanded in length to reveal a gradually unfolding, haunting soundworld. Spatialisation is central to the concept of the work: sounds are carefully positioned and moved in space to produce an unreal acoustic labyrinth surrounding the soloist

Strength of convergence and multiplicities in the spectrum of a C*-dynamical system

We consider separable $C^*$-dynamical systems $(A,G,\alpha)$ for which the induced action of the group $G$ on the spectrum $\hat A$ of the $C^*$-algebra $A$ is free. We study how the representation theory of the associated crossed-product $C^*$-algebra $A\rtimes_\alpha G$ depends on the representation theory of $A$ and the properties of the action of $G$ on $\hat A$. Our main tools involve computations of upper and lower bounds on multiplicity numbers associated to irreducible representations of $A\rtimes_\alpha G$. We apply our techniques to give necessary and sufficient conditions, in terms of $A$ and the action of $G$ on $\hat A$, for $A\rtimes_{\alpha}G$ to be (i) a continuous-trace $C^*$-algebra, (ii) a Fell $C^*$-algebra and (iii) a bounded-trace $C^*$-algebra. When $G$ is amenable, we also give necessary and sufficient conditions for the crossed-product $C^*$-algebra $A\rtimes_{\alpha}G$ to be (iv) a liminal $C^*$-algebra and (v) a Type I $C^*$-algebra. The results in (i), (iii)--(v) extend some earlier special cases in which $A$ was assumed to have the corresponding property.Comment: Publication version, to appear in Proc. London Math. So

Spectral synthesis in the multiplier algebra of a C_0(X)-algebra

We are grateful to the referee for a number of helpful comments and for pointing out an error in the original proof of Theorem 3.6.Peer reviewedPostprin

The Inner Corona Algebra of a C0(X)-Algebra

We are grateful to the referee for a number of helpful comments.Peer reviewedPostprin

The Tatler Guide to a successful magazine journalism career

The Tatler Guide to Good Journalism Tatler’s features editor Sophia Money-Coutts joined Polis in this week’s Media Agenda Talk. The former LSE student, despite being admittedly terrified of public speaking, gave an entertaining and insightful speech into the various different worlds of journalism. It would be easy to focus on the glamorous lives of the aristocracy that colour the pages and embody the audience of Tatler magazine itself, but we’ll leave that to the BBC… What was most intriguing about Sophia’s talk was that it did not focus on the clichéd narratives of England’s elite. Instead she spoke of the valuable journalistic values and lessons she has obtained along the King’s Road, presenting us with a unique Tatler ‘Top Tips Guide’ to being a good journalist in today’s media landscape as Polis intern and MSc student Emma Archbold reports

The Dixmier property and tracial states for C*-algebras

A.T. was partially supported by an NSERC Postdoctoral Fellowship and through the EPSRC grant EP/N00874X/1. Acknowledgements We are grateful to Luis Santiago for helpful discussions at an early stage of this investigation. We would also like to thank the referee for providing helpful comments, which have led to a number of improvements.Peer reviewedPublisher PD

The space of ideals in the minimal tensor product of C∗C^*-algebras

For $C^*$-algebras $A_1, A_2$ the map $(I_1,I_2)\to ker(q_{I_1}\otimes q_{I_2})$ from $Id^{\prime}(A_1)\times Id^{\prime}(A_2)$ into $Id^{\prime}(A_1\otimes_{\mathrm{min}} A_2) is a homeomorphism onto its image which is dense in the range. Here, for a$C^*$-algebra$A$, the space of all proper closed two sided ideals endowed with an adequate topology is denoted$Id^{\prime}(A)$and$q_I$is the quotient map of$A$onto$A/I$. New proofs of the equivalence of the property (F) of Tomiyama for$A_1\otimes_{\mathrm{min}} A_2$ with certain other properties are presented.Comment: 9 pages, minor mistakes were correcte

Norms of inner derivations for multiplier algebras of C ∗ -algebras and group C ∗ -algebras, II

Peer reviewedPostprin