Hello? Hello? Is this thing still on?
I've been a bit quiet here for the last few years, partly as a new parent, learning to deal with children, and more recently as an associate department head, learning to deal with bureaucracy. (The two skills are remarkably similar!) But now that my kids are now well into their transformation from cute gobs of poo into full-fledged independent human beings, and my three-year sentence term as an administrator is coming to a close, I find myself wondering what I'm going to do when I'm no longer a grown-up.
My main job as associate head was hiring tenure-track faculty. Illinois CS just had an excellent year—five new faculty are joining us this fall and several more are starting in Fall 2017—but I need to wait for the ink to dry on our final offers before talking about the hiring process in any detail.
My other job was helping to launch a major revision of our undergraduate theory courses, as part of a wider curriculum revision. Our new required theory course (CS 374) has a steady-state enrollment of 400 students per semester. This curriculum change, combined with our skyrocketing enrollments (just like everyone else's) has had some interesting side-effects, which I'm sure I'll talk more about later.
One side-effect of the change is that my algorithms lecture notes no longer mirror the structure of the courses I teach, so I'm starting a major revision. With videos. Stay tuned.
But enough about me. The title of this post is a line from a 1940's cold-reading test for prospective radio announcers, popularized by Jerry Lewis (“The Announcer's Test”), Flo and Eddie (“The Tibetan Memory Trick”), and many others. The test has the same cumulative structure as “The Twelve Days of Christmas” or some versions of “Old MacDonald Had a Farm”; the kth “verse” consists of the first k lines from the following list (with “and” inserted between like k–1 and k):
Roughly, the length of each line increases linearly, which means the length of each verse increases quadratically, which means the length of the entire announcement is cubic in the number of lines. This is the only "song" I know that requires Θ(n^{3}) time to "sing" the first n verses. On the other hand, just writing down n lines requires Θ(n^{2}) space, so in terms of Knuth's infamous paper “The Complexity of Songs”, the Announcer's Test has complexity Θ(N^{2/3}). This is the only example I know of a "song" with this complexity.
Do you know of any other songs with complexity Θ(N^{2/3})? How about Θ(N^{c}) for any constant c other than 0, 1/2, 2/3, or 1? I look forward to reading your compositions in the comments.
A new approach to crushing 3-manifold triangulations
by Benjamin A. Burton
Computing closed essential surfaces in knot complements
by Benjamin A. Burton, Alexander Coward, and Stephan Tillmann
Counting and sampling minimum cuts in genus g graphs
by Erin Chambers,
Kyle Fox,
and Amir Nayyeri
Efficiently hex-meshing things(,) with topology
by Jeff Erickson
Geometry in the space of persistence modules and diagrams
by Vin de Silva and Vidit Nanda
Graph induced complex on point data [no preprint available]
by Tamal Dey,
Fengtao Fan,
and Yusu Wang
Homological reconstruction and simplification in R^{3}
by Dominique Attali,
Ulrich Bauer,
Olivier Devillers,
Marc Glisse,
and André Lieutier.
Localized Delaunay refinement for piecewise-smooth complexes [no preprint available]
by Tamal Dey
and Andrew Slatton.
Measuring similarity between curves on 2-manifolds via homotopy area
by Erin Chambers
and Yusu Wang
Parameterized complexity of discrete Morse theory
by João Paixão,
Jonathan Spreer,
Benjamin A. Burton,
and Thomas Lewiner
Topological graphs: Empty triangles and disjoint matchings [no preprint available]
by Andres J. Ruiz-Vargas
and Radoslav Fulek
Zigzag zoology: Rips zigzags for homology inference
by Steve Oudot and Don Sheehy
I am the chair of the newly elected computational geometry steering committee; the other members are Mark de Berg, David Eppstein (secretary), Joe Mitchell, and Günter Rote. There should be an official announcement on the computational geometry mailing list in the next few days.
I am attending the CCC Leadership in Science Policy Institute next month.
Thanks to Salil Vadhan's kind invitation, I will join the SIGACT Committtee for the Advancement of Theoretical Computer Science this summer.
Here's a selection of computational geometry and topology papers accepted to SODA 2012. As usual, this list is neither exclusive nor exhaustive; for many papers, I'm just guessing about the content from the title and/or authors.
Yes, most data structure papers count.
Yes, most planar graph papers count.