Perfecting imperfection

Perfecting Kant's highest good

Understanding Imperfection

Because of their inherent abstraction, systems ideas are not themselves sufficient for gaining scientific knowledge or solving practical problems, but they can be a source of insights into the universality of imperfection, insights which can contribute to a new scientific world view. Systems theory offers a metaphysics, or more precisely an ontology, of imperfection. Through it, we can heed Spi...

Graph Imperfection

We are interested in colouring a graph G=(V, E) together with an integral weight or demand vector x=(xv : v # V) in such a way that xv colours are assigned to each node v, adjacent nodes are coloured with disjoint sets of colours, and we use as few colours as possible. Such problems arise in the design of cellular communication systems, when radio channels must be assigned to transmitters to sa...

Perfecting peptide priming

Tumors can avoid immune destruction despite being invaded by tumor-specific CD8 ϩ T cells. On page 1257, Bronte et al. describe one way that prostate tumors subdue T cells— they make two enzymes that combine forces to cripple T cell signaling components. Tumors use a variety of tactics to avoid attack by cytotoxic CD8 ϩ T cells; one is to establish an inhospitable environment that inhibits T ce...

Comparing Imperfection Ratio and Imperfection Index for Graph Classes

Perfect graphs constitute a well-studied graph class with a rich structure, reflected by many characterizations with respect to different concepts. Perfect graphs are, for instance, precisely those graphs G where the stable set polytope STAB(G) coincides with the fractional stable set polytope QSTAB(G). For all imperfect graphs G it holds that STAB(G) ⊂ QSTAB(G). It is, therefore, natural to us...