**NIU math: Ben Wallis**

**Research interests:** Banach space theory, especially Tsirelson-like and other sequence spaces, almost-invariant halfspaces, and operator ideals.

**Publications:**

"Constructing Banach ideals using upper $\ell_p$-estimates," *Extracta Mathematicae*, Vol. 29, No. 1-2 (2014), pp73-95. (pdf)

"The structure of almost-invariant half-spaces for some operators" (with Gleb Sirotkin), *Journal of Functional Analysis*, Vol. 267, Iss. 7 (2014 Oct 01), pp2298-312.

**Expected Publications:**
*The almost-invariant halfspace problem* (Ph.D. dissertation), in preparation.

"New closed ideals in $\mathcal{L}(\ell_p\oplus c_0)$ and $\mathcal{L}(\ell_1\oplus\ell_q)$ for $1 < p < 2 < q < \infty$," in preparation

"Almost-invariant and essentially-invariant halfspaces" (with Gleb Sirotkin), in preparation.

"Sequence singular operators" (with Gleb Sirotkin), in preparation.

**Talks:**

2015 Mar 03, "Constructing Banach ideals using upper $\ell_p$-estimates," seminar talk, Northern Illinois University, Dekalb, IL, USA.

2014 Oct 07, "The almost-invariant halfspace problem" (joint with Gleb Sirotkin), seminar talk, Northern Illinois University, Dekalb, IL, USA.

2014 Sep 27, "Constructing Banach ideals using upper $\ell_p$-estimates," *Wabash annual miniconference*, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA. (pdf)

2014 May 23, "Schreier-supported upper $\ell_p$-estimates on Banach space operators," *Seventh conference on function spaces*, Southern Illinois University---Edwardsville, Edwardsville, IL, USA. (pdf)

2014 Mar 07, "The almost-invariant halfspace problem" (joint with Gleb Sirotkin), seminar talk, University of Alberta, Edmonton, AB, Canada.

2013 Sep 28, "The almost-invariant halfspace problem" (joint with Gleb Sirotkin), *Wabash annual miniconference*, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA.

**Referee experience:**

Referee for *Positivity* (2014-present)

**Teaching experience:**
*At NIU:* MATH 101 (Topics in Math), 109p (Chance Program Fundamentals of Math II), 110p (Chance Program College Algebra), 155 (Trig/Precalculus), 201 (Foundations of Elementary School Math), 211 (Business Calculus), and 229 (Calculus I).
*At Kishwaukee College:* MAT 096 (Algebra I), 097 (Geometry), 098 (Algebra II), and 150 (College Algebra).

For questions or comments, you can contact me via email: `wallis@math.niu.edu`

Last updated: 2015 Feb 26