Four states are enough!

Four states are enough!

This paper presents a 1D intrinsically universal cellular automaton with four states for a first neighbors neighborhood, improving on the previous lower bound and getting nearer to the Turing universality bound. Intrinsic universality is discussed. Construction and proof rely on a combination of bulking techniques with programming using particles and collisions.

obesity dilemma: are there enough bariatric surgeons?

Two Bits are Enough

We design a congestion control protocol that uses the existing IP ECN bits to achieve efficient and fair bandwidth allocations on high Bandwidth-Delay Product (BDP) paths while maintaining low persistent queue length and negligible packet loss rate. Our protocol uses load factor as a signal of congestion and makes use of a packet marking scheme to obtain high resolution congestion estimates. Ou...

Are there compact heavy four-quark bound states?

J. Vijande, E. Weissman, A. Valcarce, and N. Barnea Departamento de Fı́sica Teórica e IFIC, Universidad de Valencia-CSIC, E-46100 Burjassot, Valencia, Spain The Racah Institute of Physics, The Hebrew University, 91904, Jerusalem, Israel Departamento de Fı́sica Fundamental, Universidad de Salamanca, E-37008 Salamanca, Spain Institute for Nuclear Theory, University of Washington, Seattle, Washingto...

Walking dynamics are symmetric (enough).

Many biological phenomena such as locomotion, circadian cycles and breathing are rhythmic in nature and can be modelled as rhythmic dynamical systems. Dynamical systems modelling often involves neglecting certain characteristics of a physical system as a modelling convenience. For example, human locomotion is frequently treated as symmetric about the sagittal plane. In this work, we test this a...