Lecturer @ FMI
Scientific Researcher @ IMAR

Biroul 209,
Facultatea de Matematică și Informatică,
Universitatea din București,
010014 București,
România.

Andrei Sipoș

### (Curriculum Vitæ, arXiv, OPC)

My research so far has been primarily located in the area of proof mining, an applied subfield of mathematical logic that aims to analyse ordinary mathematical proofs in order to obtain additional information which is not immediately apparent (for a somewhat-gentle introduction, see my ongoing series “What proof mining is about” on The Proof Theory Blog, starting here). The techniques of proof mining have been hitherto applied to various mathematical fields like convex optimization, ergodic theory, approximation theory; occasionally, my research has spilled over into those areas themselves. I started working in proof mining midway through my PhD studies at the University of Bucharest and defended my thesis, Contributions to proof mining, written under the supervision of Laurențiu Leuștean, in September 2017. This was followed by a three-year postdoc at TU Darmstadt, where my mentor was Ulrich Kohlenbach. All this time, I've held a research position at the Simion Stoilow Institute of Mathematics of the Romanian Academy; since October 2020, I am a Lecturer (Assistant Professor) in the Department of Computer Science of the University of Bucharest.

### Papers

1. “Quantitative results on the Ishikawa iteration of Lipschitz pseudo-contractions” (with Laurențiu Leuștean and Vlad Radu),
Journal of Nonlinear and Convex Analysis, Volume 17, Number 11, 2277–2292, 2016.

2. “Effective results on a fixed point algorithm for families of nonlinear mappings”,
Annals of Pure and Applied Logic, Volume 168, Issue 1, 112–128, 2017.

3. “A note on the Mann iteration for $k$-strict pseudocontractions in Banach spaces”,
Numerical Functional Analysis and Optimization, Volume 38, Issue 1, 80–90, 2017.

4. “Codensity and Stone spaces”,
Mathematica Slovaca, Volume 68, Issue 1, 57–70, 2018.

5. “An application of proof mining to the proximal point algorithm in CAT(0) spaces” (with Laurențiu Leuștean),
in: A. Bellow, C. Calude, T. Zamfirescu (eds.), Mathematics Almost Everywhere. In Memory of Solomon Marcus (pp. 153–168), World Sci. Publ., 2018.

6. “Effective strong convergence of the proximal point algorithm in CAT(0) spaces” (with Laurențiu Leuștean),
Journal of Nonlinear and Variational Analysis, Volume 2, Issue 2, 219–228, 2018.

7. “An abstract proximal point algorithm” (with Laurențiu Leuștean and Adriana Nicolae),
Journal of Global Optimization, Volume 72, Issue 3, 553–577, 2018.

8. “The asymptotic behaviour of convex combinations of firmly nonexpansive mappings”,
Journal of Convex Analysis, Volume 26, Number 3, 911–924, 2019.

9. “Proof mining in $L^p$ spaces”,
Journal of Symbolic Logic, Volume 84, Issue 4, 1612–1629, 2019.

10. “The finitary content of sunny nonexpansive retractions” (with Ulrich Kohlenbach),
Communications in Contemporary Mathematics, Volume 23, Number 1, 19550093 [63 pages], 2021.

11. “Bounds on strong unicity for Chebyshev approximation with bounded coefficients”,
arXiv:1904.10284 [math.CA], 2019. To appear in: Mathematische Nachrichten.

12. “Revisiting jointly firmly nonexpansive families of mappings”,
arXiv:2006.02167 [math.OC], 2020. To appear in: Optimization.

13. “Rates of metastability for iterations on the unit interval”,
arXiv:2008.03934 [math.CA], 2020. To appear in: Journal of Mathematical Analysis and Applications.

14. “Quantitative inconsistent feasibility for averaged mappings”,
arXiv:2001.01513 [math.OC], 2020. Submitted.

15. “Construction of fixed points of asymptotically nonexpansive mappings in uniformly convex hyperbolic spaces”,
arXiv:2008.03930 [math.MG], 2020. Submitted.

16. “A quantitative multi-parameter mean ergodic theorem”,
arXiv:2008.03932 [math.DS], 2020. Submitted.