**NIU math: Ben Wallis**

**Research interests:** My primary area of interest lies in Banach space theory, with a current focus in the study of almost-invariant halfspaces, Tsirelson-like and Lorentz-like sequence spaces, and operator ideals.

**Publications:**

"Closed ideals in \mathcal{L}(X) and \mathcal{L}(X^*) when X contains certain copies of \ell_p and c_0," *Operators and Matrices* 10:2 (2016) pp285-318. (pdf)

"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. (pdf)

**Accepted Publications:**

"Sequence-singular operators" (with Gleb Sirotkin), to appear in *Journal of Mathematical Analysis and Applications*. arXiv:1509.01485v1 [math.FA] (pdf)

"Almost-invariant and essentially-invariant halfspaces" (with Gleb Sirotkin), to appear in *Linear Algebra and its Applications*. arXiv:1509.07428v1 [math.FA] (pdf)

**Submitted Publications:**

"Classes of operators determined by ordinal indices" (with Kevin Beanland, Ryan Causey, and Daniel Freeman). arXiv:1507.06285v1 [math.FA] (pdf)

**Invited talks:**

2015 Oct 19, "Closed ideals in \mathcal{L}(X) and \mathcal{L}(X^*) when X contains certain copies of \ell_p and c_0." (joint with Gleb Sirotkin), *Fall Southeastern Sectional Meeting*, University of Memphis, Memphis, TN, Meeting #1113, AMS Sectional Meeting Program.

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

2014 Nov 14, "Continuums of closed ideals in operator algebras," seminar talk, St. Louis University, St. Louis, MO, USA.

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

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

**Contributed talks:**

2015 Sep 12, "Closed ideals in \mathcal{L}(X) and \mathcal{L}(X^*) when X contains certain copies of \ell_p and c_0." (joint with Gleb Sirotkin), *Wabash annual miniconference*, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA.

2015 Jun 09, "Constructing Banach ideals using upper \ell_p-estimates," *Relations Between Banach Space Theory and Geometric Measure Theory*, University of Warwick, Coventry, UK. (youtube)

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)

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), 229 (Calculus I), and 230 (Calculus II).
*At Kishwaukee College:* MAT 096 (Algebra I), 097 (Geometry), 098 (Algebra II), 150 (College Algebra), and 220 (Business Statistics).
*At Waubonsee Community College:* MTH 131 (Calculus I) and 236 (Intro Linear Algebra).

For questions or comments, you can contact me via email: `benwallis@live.com`

Last updated: 2016 Jun 17