I am currently employed as lecturer at the University of Pretoria. My current research centers around the Lipschitz structure of Banach spaces and ordered Banach spaces
I previously (2016-2017) held a Claude Leon postdoctoral fellowship at the University of Pretoria.
I previously (2014-2015) held a postdoctoral fellowship at the North-west University working in collaboration with Sanne ter Horst.
I completed my PhD at Leiden University in November of 2013 under supervision of Marcel de Jeu, with thesis titled Positive representations on ordered Banach spaces.
Office: University of Pretoria (Hatfield); Botany Building; Room 2-7.
Strong Klee-Andô Theorems through an Open Mapping Theorem for cone-valued multi-functions
Journal of Functional Analysis. (to appear)
A Pointwise Lipschitz Selection Theorem
Set-Valued and Variational Analysis. (to appear)
On compact packings of the plane with circles of three radii
S. ter Horst, M. Messerschmidt, A.C.M. Ran, M. Roelands, M. Wortel
Equivalence after extension and Schur coupling coincide for inessential operators
Indagationes Mathematicae (N.S.) 29 (2018), no. 5, 1350--1361.
M. Messerschmidt and M. Wortel
The intrinsic metric on the unit sphere of a normed space
S. ter Horst, M. Messerschmidt, A. Ran
Equivalence after extension for compact operators on Banach spaces
Journal of Mathematical Analysis and Applications. 431 (2015), pp. 136–149
Geometric duality theory for cones in dual pairs of vector spaces
Journal of Functional Analysis. 269 (2015), pp. 2018-2044
Normality of spaces of operators and quasi-lattices
Positivity. 19 (2015), pp. 695-724
M. de Jeu, M. Messerschmidt, and M. Wortel
Crossed products of Banach algebras. II
Dissertationes Mathematicae. (To appear)
M. de Jeu, and M. Messerschmidt
Crossed products of Banach algebras. III
Dissertationes Mathematicae (To appear)