The primacy model and the structure of olfactory space
Fig 2
Primacy hull in higher dimensions.
A. Geometrical representation of primacy sets for different primacy numbers: p = 2: 1-simplex, a segment; p = 3: 2-simplex, a triangle; p = 4: 3-simplex, tetrahedron. B. An example of primacy hull for a random set of points in 2D (p = 2). A primacy hull is a set of simplexes that reside on the extremes of the given set of points. C. A primacy hull for D = 3, p = 3. A ~2D surface is tessellated by triangles, each of them representing an independent odor identity. D. The same for D = 6, p = 7. 6D manifold is projected onto 3D space for visualization. E. Decomposition of affinity matrix K into two low-dimensional matrices: Q is a low-dimensional matrix of basic odor features and R is a matrix of receptor affinities for these basic features.