The lecture by Jaap Klaarenbeek examines the complex relationships between formal and informal urban practices in São Paulo, particularly in favelas, highlighting how informal systems operate within and outside formal structures. It discusses the dynamic nature of informal economies, self-management in housing, and social relations shaped by collective initiatives amidst a backdrop of urban growth and neglect. The document underscores the necessity of recognizing informal settlements as stable urban typologies rather than transient phenomena.