We define a bivariate polynomial for unlabeled rooted trees and show that the of an tree T is generating function class subtrees . prove complete isomorphism invariant trees. Then, we generalize to unrooted generalized

We revisit the different approaches used in the literature to estimate the data complexity of distinguishing attacks on stream ciphers and analyze their inter-relationships. In the process, we formally argue which approach is applicable (or not applicable) in what scenario. To our knowledge, this is the first kind of such an exposition. We also perform a rigorous statistical analysis of the mes...

We present data and argument to show that in Tetris|a real-time, interactive video-game|certain cognitive and perceptual problems are more quickly, easily, and reliably solved by performing actions in the world than by performing computational actions in the head alone. We have found that some of the translations and rotations made by players of this video-game are best understood as actions th...