A system for automatically deriving a Schenkerian reduction of an extract of tonal music is described. Schenkerian theory is formalised in a quasi-grammatical manner, expressing a reduction as a binary-tree structure. Computer software which operates in the manner of a chart parser using this grammar has been implemented, capable of deriving a matrix of reduction possibilities, in polynomial time, from a representation of the score. A full reduction of the extract can be discovered by selecting a tree from this matrix. The number of possible valid reductions for even short extracts is found to be extremely large, so criteria are required to distinguish good reductions from bad ones. To find such criteria, themes from five Mozart piano sonatas are analysed and samples of ‗good' reductions (defined by reference to pre-existing analyses of these themes) are compared with randomly sampled reductions. Nine criteria are thereby derived, which can be applied in the process of parsing and selecting a reduction. The results are promising, but the process is still too computationally expensive-only extracts of a few bars in length can be reduced-and more extensive testing is required before the system can be properly claimed to perform automatic Schenkerian analysis.

The usefulness and desirability of representation schemes which explicitly show musical structure has often been commented upon. A particular aim of music theory and analysis has been to describe and derive musical structure, and this article discusses computational systems based on this work. Six desirable properties of a structural representation are described: that it should be constructive, derivable, meaningful, decomposable, hierarchical, and generative. Previous computational work based on the generative and reductional theories of Schenker and of Lerdahl and Jackendoff is examined in the light of these properties. Proposals are made for a representational framework which promises the desirable properties. The framework shares characteristics with earlier work but does not use pure trees as a representational structure, instead allowing joining of branches in limited circumstances to make directed acyclic graphs. Important issues in developing a representation scheme within this framework are discussed, especially concerning the representation of polyphonic music, of rhythmic patterns, and of up-beats. An example is given of two alternative representations within this framework of the same segment of music used to exemplify earlier work: the opening of the theme of Mozart's piano sonata in A major, K.331.

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The nature of melodic similarity is interrogated through a survey of the different means by which the phenomenon has been studied, examination of methods for measuring melodic similarity, a Monte Carlo analysis of data from the experiment which formed the basis for the 'ground truth' used in the MIREX 2005 contest on melodic similarity, and examples of interest in the music of Mozart. Melodic similarity has been studied by a number of means, sometimes quite contrasting, which lead to important differences in the light of the finding that similarity is dependent on context. Models of melodic similarity based on reduction show that the existence of multiple possible reductions forms a natural basis for similarity to depend on interpretation. Examination of the MIREX 2005 data shows wide variations in subjects' judgements of melodic similarity and some evidence that the perceived similarity between two melodies can be influenced by the presence of a third melody. Examples from Mozart suggest that he deliberately exploited the possibilities inherent in recognising similarity through different interpretations. It is therefore proposed that similarity be thought of not as a distinct and definite function of two melodies but as something created in the minds of those who hear the melodies.

Skin changes associated with long term hydroxyurea therapy have only rarely been reported and are not widely known. This report concerns a patient in whom extensive and debilitating skin changes developed secondary to hydroxyurea therapy. In addition to previously reported manifestations such as ichthyosis, a dermatomyositis-like eruption on the dorsal hands, facial erythema and accelerated development of premalignant and malignant skin lesions, the patient developed an erosive eruption on the glans penis. He also developed a rapidly enlarging viral wart which clinically resembled a squamous cell carcinoma and histologically showed marked cytological atypia. It is possible that hydroxyurea caused accelerated photoageing and also contributed to the rapid growth of the viral wart and the atypical histological features. The time course of the clinical changes suggests that they result from direct toxicity of hydroxyurea on the basal layer of the epidermis and mucosal surfaces.