Uta Gelbke (2016), Urban Zero Points: Indeterminate Public Space and the Utopia of DIY Urbanism, Institute of Architecture Technology; 1st reviewer: Roger Riewe, 2nd reviewer: Bart Lootsma; 340 pages, English.

The doctoral thesis investigates the relevance of indeterminate public space, defined as urban zero points, for the political empowerment of local agents in urban environments in the form of DIY urbanism. Ever since industrialization and the triumph of the rational plan, defining the physical and non-physical features of the city fell to the supremacy of politicians, planners, and investors. As opposed to the traditional aestheticization and marketing of the city through urban regeneration, DIY urbanism signifies both an alternative way of urban planning and the re-negotiation of existing power relations in the city. The thesis examines to what extent the architectural and spatial parameters of the public realm inspire and empower their respective users to self-organized planning. Zero points are understood as vacant, functionally not predefined yet physically clearly framed places in the city. Whether implemented in the urban fabric through planning or emerging as a consequence of other modifications of the city, they are discussed as a prerequisite of new ways of spatial appropriation and interaction amongst different urban actors. The lack of authority and hierarchic structure in urban zero points facilitates the empowerment of individuals or groups vis-à-vis traditional decision-makers, or in other words, the emergence of political subjects. The investigation is assisted by three exemplary projects—regeneration in Barcelona, Budapest, and Berlin in the aftermath of formal political change—and the theoretical frameworks of urban regeneration, spatial perception, and political subjectivity. It combines literature and plan analysis, and is complemented by expert interviews. The thesis expands the range of conceptualizations of indeterminacy in urban studies by linking architectural-spatial parameters to socio-political implications and by providing a specific set of properties that seem relevant in this light. Beyond the romanticized vision of self-organization, the thesis offers a critique of the concept of DIY urbanism. While it appears to succeed in involving a variety of people in unauthorized productions of space, it also raises concern with regard to issues such as exclusion or the longevity of results. Spatial settings aside, political subjectification is hinged on additional parameters, notably a high level of cultural capital. Thus, the concept of zero points does not present a blueprint for future articulations of public space. On the grounds of this retrospective analysis, it rather displays spatial qualities such as maintaining a sense of ‘no authority’ in order to encourage the formation of political subjects.