John+Tromp

a Dutch mathematician and computer scientist with a Ph.D. in 1993 on algorithms and [|complexity] from [|University of Amsterdam] under advisor Paul Vitányi. His research interests include artificial intelligence and board games such as Connect Four, Chess and Go, complexity, [|algorithmic information theory], [|distributed computing], and [|computational biology]. His recreational interests include playing Go and chess. He was affiliated with the [|Centrum Wiskunde & Informatica (CWI)] and currently resides in [|Long Island], [|New York]. || toc =Number of Positions= John Tromp has researched on counting the number of legal positions in Go and reachable chess positions, and gives an upper bound of (about 10^45.888 or ~ 2^152.437) on the number of chess positions, but states, like the bound of ~10^46.25 published by Shirish Chinchalkar, that it requires better documentation to be considered verifiable. On January 20, 2016, the number of legal positions on a standard size Go board was determined to be : code L19 = 208168199381979984699478633344862770286522453884530548425639456820927419612738015378525648451698519643907259916015628128546089888314427129715319317557736620397247064840935 code or more compact code 2081681993819799846 9947863334486277028 6522453884530548425 6394568209274196127 3801537852564845169 8519643907259916015 6281285460898883144 2712971531931755773 6620397247064840935 code The approximation code L19 ~ 2.081681994 * 10^170 code has been known since 2006. So what took 10 years to nail it down to the last digit?
 * Home * People * John Tromp**
 * [[image:JOHN0.jpg link="https://tromp.github.io/"]] ||~ || **Johannes (John) Theodorus Tromp**,
 * John Tromp ||~ ||^ ||

=Selected Publications=

1989

 * John Tromp (**1989**). //How to Construct an Atomic Variable (Extended Abstract)//. [|WDAG 1989]

1990 ...

 * [|Yehuda Afek], [|Eli Gafni], John Tromp, Paul M. B. Vitányi (**1992**). //Wait-free Test-and-Set (Extended Abstract)//. [|WDAG 1992]
 * John Tromp (**1993**). //[|Aspects of Algorithms and Complexity]//. Ph.D. thesis, [|University of Amsterdam], advisor Paul M. B. Vitányi
 * John Tromp, Jeffrey Shallit (**1995**). //Subword Complexity of a Generalized Thue-Morse Word//. [|Information Processing Letters], Vol. 54, No. 6
 * [|Ming Li], John Tromp, Paul M. B. Vitányi (**1996**). //How to Share Concurrent Wait-Free Variables//. Journal of the ACM, Vol. 43, No. 4

2000 ...

 * Marcel Crâşmaru, John Tromp (**2000**). //[|Ladders Are PSPACE-Complete]//. CG 2000
 * John Tromp, Paul M. B. Vitányi (**2001**). //Randomized Two-Process Wait-Free Test-and-Set//. [|CoRR]
 * John Tromp, Paul M. B. Vitányi (**2002**). //A Protocol for Randomized Anonymous Two-process Wait-free Test-and-Set with Finite-state Verification//. [|SIROCCO]
 * John Tromp (**2006**). //Binary Lambda Calculus and Combinatory Logic//. [|Kolmogorov Complexity and Applications]
 * John Tromp, Gunnar Farnebäck (**2006**). //[|Combinatorics of Go]//. CG 2006
 * John Tromp, Gunnar Farnebäck (**2009**). //Combinatorics of Go//. (revised version of the CG 2006 paper), [|ps]

2010 ...

 * Ingo Althöfer (**2011**). //John Tromp in the Style of David Levy: 4-0 win in the Go bet//. ICGA Journal, Vol. 34, No. 2
 * John Tromp (**2014**). //[|Cuckoo Cycle: a memory-hard proof-of-work system]//. [|IACR Cryptology ePrint Archive]
 * John Tromp (**2016**). //The number of legal Go positions//. CG 2016
 * John Tromp, Matthieu Walraet (**2016**). //A googolplex of Go games//. CG 2016

=Postings=
 * [|entropy of chess positions] by John Tromp, rgc, April 15, 1991
 * [|Number of Go positions computed at last] by John Tromp, [|The Computer-go Archives], January 22, 2016
 * [|longest 3x3 game] by John Tromp, [|Computer Go Archive], February 18, 2016

=External Links= > [|John's Chess Playground] > [|John's Connect Four Playground] » Connect Four > [|John's Go Page] » Go > [|Counting Legal Positions in Go], January 20, 2016 > [|Programming Pearls]
 * [|John Tromp HomePage]
 * [|The Mathematics Genealogy Project - Johannes Tromp]
 * [|John Tromp at Sensei's Library]
 * [|John Tromp | LinkedIn]

=References= =What links here?= include page="John Tromp" component="backlinks" limit="40"
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