Dr Ian Morris
Reader in Mathematics
Director of the Mathematics MSc
School of Mathematical Sciences
Queen Mary University of London
Queen Mary University of London
Research
Ergodic theory, Fractal geometry, Matrix analysis
Publications
Publications of specific relevance to the Centre for Complex Systems2026
Thermodynamic formalism of countably generated self-affine setsKäenmäki A Morris I
Transactions of The American Mathematical Society, American Mathematical Society (Ams)
13-02-2026
2025
On marginal growth rates of matrix productsVarney J Morris ID
Linear Algebra and Its Applications, Elsevier vol. 709, 132-163.
01-03-2025
2024
A Stability Dichotomy for Discrete-Time Linear Switching Systems in Dimension TwoMorris ID
Siam Journal on Control and Optimization, Society For Industrial & Applied Mathematics (Siam) vol. 62 (1), 400-414.
31-01-2024
An Irreducible Linear Switching System Whose Unique Barabanov Norm Is Not Strictly ConvexMorris ID
Siam Journal on Control and Optimization, Society For Industrial & Applied Mathematics (Siam) vol. 62 (1), 42-64.
10-01-2024
2023
A note on the marginal instability rates of two-dimensional linear cocyclesMorris ID Varney J
Dynamical Systems, Taylor & Francis vol. 38 (4), 525-540.
21-06-2023
2022
A converse statement to Hutchinson’s theorem and a dimension gap for self-affine measuresMorris ID Sert Ç
Journal of The European Mathematical Society, European Mathematical Society - Ems - Publishing House vol. 25 (11), 4315-4367.
11-11-2022
On affine iterated function systems which robustly admit an invariant affine subspaceMorris ID
Proceedings of The American Mathematical Society, American Mathematical Society (Ams) vol. 151 (01), 101-112.
07-10-2022
On dense intermingling of exact overlaps and the open set conditionMorris ID
Proceedings of The Edinburgh Mathematical Society, Cambridge University Press (Cup) vol. 65 (3), 747-759.
01-08-2022
Marginally unstable discrete-time linear switched systems with highly irregular trajectory growthMorris ID
Systems & Control Letters, Elsevier vol. 163
01-05-2022
Fast approximation of the affinity dimension for dominated affine iterated function systemsMorris ID
Annales Fennici Mathematici, Finnish Mathematical Society vol. 47 (2), 645-694.
13-04-2022
Fast Approximation of the $p$-Radius, Matrix Pressure, or Generalized Lyapunov Exponent for Positive and Dominated MatricesMorris ID
Siam Journal on Matrix Analysis and Applications, Society For Industrial & Applied Mathematics (Siam) vol. 43 (1), 178-198.
10-02-2022
2021
A strongly irreducible affine iterated function system with two invariant measures of maximal dimensionMorris ID Sert C
Ergodic Theory and Dynamical Systems vol. 41 (11), 3417-3438.
30-11-2021
How long is the chaos game?Morris ID Jurga N
Bulletin of The London Mathematical Society, Wiley vol. 53 (6), 1749-1765.
20-09-2021
Totally Ergodic Generalised Matrix Equilibrium States have the Bernoulli PropertyMorris ID
Communications in Mathematical Physics, Springer Nature vol. 387 (2), 995-1050.
14-09-2021
Lq-spectra of self-affine measures: Closed forms, counterexamples, and split binomial sumsFraser JM Lee LD Morris ID Yu H
Nonlinearity vol. 34 (9), 6331-6357.
01-09-2021
Prevalent uniqueness in ergodic optimisationMorris ID
Proceedings of The American Mathematical Society, American Mathematical Society (Ams) vol. 149 (4), 1631-1639.
09-02-2021
2020
Domination, almost additivity, and thermodynamic formalism for planar matrix cocyclesBárány B Käenmäki A Morris ID
Israel Journal of Mathematics, Springer Nature vol. 239 (1), 173-214.
01-08-2020
Analyticity of the affinity dimension for planar iterated function systems with matrices which preserve a coneJurga N Morris ID
Nonlinearity, Iop Publishing vol. 33 (4), 1572-1593.
17-02-2020
2019
Effective estimates on the top Lyapunov exponents for random matrix productsJurga N Morris I
Nonlinearity, Iop Publishing vol. 32 (11), 4117-4146.
26-09-2019
Characterization of dominated splittings for operator cocycles acting on Banach spacesBlumenthal A Morris ID
Journal of Differential Equations, Elsevier vol. 267 (7), 3977-4013.
01-09-2019
An explicit formula for the pressure of box-like affine iterated function systemsMorris ID
Journal of Fractal Geometry Mathematics of Fractals and Related Topics, European Mathematical Society - Ems - Publishing House vol. 6 (2), 127-141.
21-03-2019
2018
On equality of Hausdorff and affinity dimensions, via self-affine measures on positive subsystemsMorris ID Shmerkin P
Transactions of The American Mathematical Society, American Mathematical Society (Ams) vol. 371 (3), 1547-1582.
17-10-2018
Some observations on Käenmäki measuresMorris ID
, Finnish Mathematical Society vol. 43, 945-960.
01-08-2018
Equilibrium states of generalised singular value potentials and applications to affine iterated function systemsBochi J Morris ID
Geometric and Functional Analysis, Springer Nature vol. 28 (4), 995-1028.
24-04-2018
2017
A necessary and sufficient condition for a matrix equilibrium state to be mixingMORRIS ID
Ergodic Theory and Dynamical Systems, Cambridge University Press (Cup) vol. 39 (8), 2223-2234.
04-12-2017
Structure of equilibrium states on self‐affine sets and strict monotonicity of affinity dimensionKäenmäki A Morris ID
Proceedings of The London Mathematical Society, Wiley vol. 116 (4), 929-956.
30-11-2017
Generic properties of the lower spectral radius for some low-rank pairs of matricesMorris ID
Linear Algebra and Its Applications, Elsevier vol. 524, 35-60.
01-07-2017
Lyapunov-maximizing measures for pairs of weighted shift operatorsMORRIS ID
Ergodic Theory and Dynamical Systems, Cambridge University Press (Cup) vol. 39 (1), 225-247.
04-05-2017
Ergodic properties of matrix equilibrium statesMORRIS ID
Ergodic Theory and Dynamical Systems, Cambridge University Press (Cup) vol. 38 (6), 2295-2320.
14-03-2017
On Falconer's formula for the generalised Rényi dimension of a self-affine measureMorris ID
, Finnish Mathematical Society vol. 42, 227-238.
01-02-2017
2016
An inequality for the matrix pressure function and applicationsMorris ID
Advances in Mathematics, Elsevier vol. 302, 280-308.
01-10-2016
A rigorous version of R.P. Brent's model for the binary Euclidean algorithmMorris ID
Advances in Mathematics, Elsevier vol. 290, 73-143.
01-02-2016
2015
A note on configurations in sets of positive density which occur at all large scalesMorris ID
Israel Journal of Mathematics, Springer Nature vol. 207 (2), 719-738.
28-03-2015
2014
Continuity properties of the lower spectral radiusBochi J Morris ID
Proceedings of The London Mathematical Society, Wiley vol. 110 (2), 477-509.
02-12-2014
2013
On a devil’s staircase associated to the joint spectral radii of a family of pairs of matricesMorris ID Sidorov N
Journal of The European Mathematical Society, European Mathematical Society - Ems - Publishing House vol. 15 (5), 1747-1782.
21-07-2013
Extremal sequences of polynomial complexityHARE KG MORRIS ID SIDOROV N
Mathematical Proceedings of The Cambridge Philosophical Society, Cambridge University Press (Cup) vol. 155 (2), 191-205.
02-05-2013
Mather sets for sequences of matrices and applications to the study of joint spectral radiiMorris ID
Proceedings of The London Mathematical Society, Wiley vol. 107 (1), 121-150.
16-01-2013
2012
The generalised Berger–Wang formula and the spectral radius of linear cocyclesMorris ID
Journal of Functional Analysis, Elsevier vol. 262 (3), 811-824.
01-02-2012
A New Sufficient Condition for the Uniqueness of Barabanov NormsMorris ID
Siam Journal on Matrix Analysis and Applications, Society For Industrial & Applied Mathematics (Siam) vol. 33 (2), 317-324.
01-01-2012
2011
An explicit counterexample to the Lagarias–Wang finiteness conjectureHare KG Morris ID Sidorov N Theys J
Advances in Mathematics, Elsevier vol. 226 (6), 4667-4701.
01-04-2011
2010
A rapidly-converging lower bound for the joint spectral radius via multiplicative ergodic theoryMorris ID
Advances in Mathematics, Elsevier vol. 225 (6), 3425-3445.
01-12-2010
Criteria for the stability of the finiteness property and for the uniqueness of Barabanov normsMorris ID
Linear Algebra and Its Applications, Elsevier vol. 433 (7), 1301-1311.
01-12-2010
Ergodic optimization for generic continuous functionsMorris ID
Discrete and Continuous Dynamical Systems, American Institute of Mathematical Sciences (Aims) vol. 27 (1), 383-388.
01-01-2010
2009
The Mañé–Conze–Guivarc’h lemma for intermittent maps of the circleMORRIS ID
Ergodic Theory and Dynamical Systems, Cambridge University Press (Cup) vol. 29 (5), 1603-1611.
03-02-2009
2008
Lyapunov optimizing measures for C1 expanding maps of the circleJENKINSON O MORRIS ID
Ergodic Theory and Dynamical Systems, Cambridge University Press (Cup) vol. 28 (6), 1849-1860.
15-10-2008
Approximating the maximum ergodic average via periodic orbitsCOLLIER D MORRIS ID
Ergodic Theory and Dynamical Systems, Cambridge University Press (Cup) vol. 28 (4), 1081-1090.
01-08-2008
Maximizing measures of generic Hölder functions have zero entropyMorris ID
Nonlinearity, Iop Publishing vol. 21 (5), 993-1000.
04-04-2008
2007
A sufficient condition for the subordination principle in ergodic optimizationMorris ID
Bulletin of The London Mathematical Society, Wiley vol. 39 (2), 214-220.
13-02-2007
Entropy for Zero-Temperature Limits of Gibbs-Equilibrium States for Countable-Alphabet Subshifts of Finite TypeMorris ID
Journal of Statistical Physics, Springer Nature vol. 126 (2), 315-324.
01-01-2007
Continuity and approximability of competitive spectral radiiGaubert S Marchesini L Akian M Morris I
2025 64th IEEE Conference on Decision and Control 10 Dec 2025 - 12 Dec 2025.
Grants
Grants of specific relevance to the Centre for Complex SystemsAn ergodic optimisation approach to stability of linear switched systemsIan Morris
£189,097 Leverhulme Trust
01-10-2025 - 30-09-2028
Lower bounds for lyapunov exponents - GRANT TRANSFERIan Morris
£132,133 Leverhulme Trust
01-09-2020 - 15-07-2022
Research Group
PhD Students
- Eng-Jon Ong
Pisot S-Adic Shifts and Discrete Spectrum. - Ewan Cameron Philip
Ergodic Optimisation of Switched Linear Differential Equations
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