Perfection Is at Its Heart Story

Testing perfection is hard

A graph property P is strongly testable if for every fixed > 0 there is a one-sided -tester for P whose query complexity is bounded by a function of . In classifying the strongly testable graph properties, the first author and Shapira showed that any hereditary graph property (such as P the family of perfect graphs) is strongly testable. A property is easily testable if it is strongly testable ...

Protein crystal perfection and its application.

Knowledge of protein crystal perfection in theory and practice is reviewed. X-ray methods of assessing perfection such as mosaicity, topography and reciprocal-space mapping are described. X-ray diffraction physics applications of protein crystals such as in Laue geometry, the large-angle oscillation technique and forming polychromatic profiles across diffraction spots are covered. Cryo- and roo...

Doping destroys the story at the heart of cycling.

SIR — Suggesting that the Tour de France should lead the way for other sports by permitting drug enhancement, as your recent Editorial ‘A sporting chance’ (Nature 448, 512; 2007) does, misses an important point. You fail to recognize the reason why people drive 10 hours to watch the regional final of college basketball, wake up in the middle of the night to watch the inevitable penalty shoot-ou...

One Mother's Heart Story.

Trembling hand perfection is NP-hard

It is NP-hard to decide if a given pure strategy Nash equilibrium of a given three-player game in strategic form with integer payoffs is trembling hand perfect.