National Institute of Informatics, Tokyo, Japan

Biography

I am a PostDoc at the National Institute of Informatics, Tokyo. I am interested in almost everything TCS/ Computational Complexity related but my focus is on arithmetic circuit complexity. You can find a list of my current publications in my DBLP or Google Scholar. A more selected view with abstracts can be found on this homepage under Publication. Apart from my main interest in Computational Complexity, I also have many other interest such as programming (as you can see from my github), machine learning,Video Game Making and Music Production. You can find my Academic CV and my software focused CV. I sometimes write posts on either TCS or Games Mechanics.

Selected Projects

Toukakoukan A way to split bills by automatically calculating who how much. Uses rust, svelte, daisyui, tailwindcss, typescript, javascript and is a PWA.

Musicbrainz Release Grabber Grabs new release from the musicbrainz database. Parses directory names, finds the corresponding UUID and checks for new releases using the XML api. Using Rust.

TheoryGrabber Fetch various TCS papers from ECCC and arxiv, downloads them puts them in a folder. Using Rust.

SerieViewer A simple interface in Qt to show shows and remember which episode I am in. Simple to start the next episode with one button press if available.
Viola A music player written in Rust with a frontend of GTK. It supports playlists, smart playlists, library view and much more. Over time, I moved the frontend to React, Typescript with the backend in Rust. Recently, Changed the frontend to Rust with seed-rs, yew and Web Assembly.

Recent Publications

ECCC

ArXiV

Conferences

2022 - Sankardeep Chakraborty and Christian Engels - Lower Bounds for Lexicographical {DFS} Data Structures - Data Compression Conference, {DCC} 2022, Snowbird, UT, USA, March 22-25, 2022
2019 - Markus Bl{\"a}ser and Christian Engels - Parameterized Valiant's Classes - 14th International Symposium on Parameterized and Exact Computation, {IPEC} 2019, September 11-13, 2019, Munich, Germany
2018 - Suryajith Chillara and Christian Engels and Nutan Limaye - A Near-Optimal Depth-Hierarchy Theorem for Small-Depth Multilinear Circuits - 59th {IEEE} Annual Symposium on Foundations of Computer Science, {FOCS} 2018, Paris, France, October 7-9, 2018
2017 - Christian Engels and B. V. Raghavendra Rao and Karteek, Sreenivasaiah - On {\textbackslash}varSigma {\textbackslash}wedge {\textbackslash}varSigma {\textbackslash}wedge {\textbackslash}varSigma Circuits: The Role of Middle {\textbackslash}varSigma Fan-In, Homogeneity and Bottom Degree - Fundamentals of Computation Theory - 21st International Symposium, {FCT} 2017, Bordeaux, France, September 11-13, 2017, Proceedings
2016 - Christian Engels and B. V. Raghavendra Rao - On Hard Instances of Non-Commutative Permanent - Computing and Combinatorics - 22nd International Conference, {COCOON} 2016, Ho Chi Minh City, Vietnam, August 2-4, 2016, Proceedings
2015 - Christian Engels - Dichotomy Theorems for Homomorphism Polynomials of Graph Classes - {WALCOM:} Algorithms and Computation - 9th International Workshop, {WALCOM} 2015, Dhaka, Bangladesh, February 26-28, 2015. Proceedings
2013 - Karl Bringmann and Christian Engels and Bodo Manthey and B. V. Raghavendra Rao - Random Shortest Paths: Non-euclidean Instances for Metric Optimization Problems - Mathematical Foundations of Computer Science 2013 - 38th International Symposium, {MFCS} 2013, Klosterneuburg, Austria, August 26-30, 2013. Proceedings
2012 - Christian Engels and Bodo Manthey and B. V. Raghavendra Rao - Random Shortest Path Metrics with Applications - 11th Cologne-Twente Workshop on Graphs and Combinatorial Optimization, Munich, Germany, May 29-31, 2012. Extended Abstracts
2011 - Markus Bl{\"a}ser and Christian Engels - Randomness Efficient Testing of Sparse Black Box Identities of Unbounded Degree over the Reals - 28th International Symposium on Theoretical Aspects of Computer Science, {STACS} 2011, March 10-12, 2011, Dortmund, Germany

Journals

2020 - Christian Engels and Mohit Garg and Kazuhisa Makino and Anup Rao - On Expressing Majority as a Majority of Majorities - {SIAM} J. Discret. Math.
2020 - Christian Engels and B. V. Raghavendra Rao - On hard instances of non-commutative permanent - Discret. Appl. Math.
2016 - Christian Engels - Dichotomy Theorems for Homomorphism Polynomials of Graph Classes - J. Graph Algorithms Appl.
2015 - Karl Bringmann and Christian Engels and Bodo Manthey and B. V. Raghavendra Rao - Random Shortest Paths: Non-Euclidean Instances for Metric Optimization Problems - Algorithmica
2009 - Christian Engels and Bodo Manthey - Average-case approximation ratio of the 2-opt algorithm for the {TSP} - Oper. Res. Lett.

Posts

Brothers - In the Nick of Time

"Brothers - A tale of two sons" is a well renowned game and one of the indie darlings from 2013. I recently played through it and can now give my assessment of this. Normally I do not care about spoiler warnings as I assume everybody does either not care or already knows the game. Second, most spoiler warning can actually already be a spoiler. Here I might break with my tradition. After a break there will be full spoilers, you are warned.

I should also mention that the game did not quite capture me as many other people. The reasons are many fold. I wanted to finish this highly acclaimed game already and know what people are talking about. ...more

July 06, 2015 [Games]

E3 and the Marketing Monster

And upon us is the current E3. The marketing machine is buzzing, the internet is excited, everybody is watching the keynotes. At the moment I only watched the Bethesda Keynote with all their glory but I am sitting ready for the Microsoft one. Why am I watching these? Because they are lame and funny and crazy and a lot more. ...more

June 16, 2015 [Games]

Player Disconnect and The Last of Us

"The Last Of Us" got wide critical acclaim from most gaming press and even most independent reviewers and analysts claim it a landmark of the current genre. Most of them mention that the ludonarrative dissonance which plagues a lot of modern games was careful avoided. The story is about a fight for survival in a world without any resources and enemies all around and the gameplay is about the same aspects. It is fast, deadly and easily ends in panic. When you sneak up on the next infected, gathering all the supplies you can find, you wonder just how you are going to get past them with only a nailbomb and 3 shotgun shells. ...more

April 29, 2015 [Games]