Traditional requirements engineering approaches suffer from the tyranny of the dominant decomposition, with functional requirements serving as the base decomposition and non-functional requirements cutting across them. In this paper, we propose a model that decomposes requirements in a uniform fashion regardless of their functional or non-functional nature. This makes it possible to project any particular set of requirements on a range of other requirements, hence supporting a multi-dimensional separation. The projections are achieved through composition rules employing informal, often concern-specific, actions and operators. The approach supports establishment of early trade-offs among crosscutting and overlapping requirements. This, in turn, facilitates negotiation and decision-making among stakeholders.