The Kalton years 2010-2025

A workshop in homage to Nigel Kalton

May 19-22, 2026
IMUEx, Badajoz, Spain
Nigel Kalton Workshop

Click HERE for more info about this image.

Nigel Kalton was an extraordinary mathematician and an important, influential source of inspiration for the Banext group at Extremadura -- not to mention how much those of us lucky enough to have met Nigel miss him. In May 2026, it will be twenty years since the fabulous Banach Spaces and their Applications in Analysis conference in honor of Nigel's 60th birthday, held at Miami University, Oxford, Ohio; and eleven since its follow-up at the CIRM in Luminy. Following that tradition, we are organizing this workshop focused on Banach space theory and related areas.

The workshop will be structured into four panels.

Panel 1. About Nigel's life and work.

Speakers: F. Albiac, J.M.F. Castillo, B. Randrianantoanina.

Panel 2. These ones Nigel didn't see coming.

Plenary lectures on results obtained after his passing that would probably have surprised him -- though this is hard to claim given his sharp mathematical intuition.

Speakers: J.L. Ansorena, F. Cabello Sánchez, G. Lancien, G. Plebanek, N. de Rancourt, P. Scholze, P. Tradacete.

Panel 3. Advances on selected topics.

Invited talks about new advances in topics dear to Nigel.

Speakers: F. Baudier, B.M. Braga, W.H.G. Correa, W. Cuellar, A. Fovelle, R. Pino.

Panel 4. Communications from participants.

The Workshop will take place at the Instituto de Matemáticas de la Universidad de Extremadura, Badajoz, Spain, from Tuesday, May 19 until Friday, May 22, 2026. If you wish to participate please fill out the Registration form HERE and do not hesitate to contact the Organizing Committee or email for any assistance.

Organizing Committee:

Félix Cabello Sánchez,

Javier Cabello Sánchez,

Jesús M. F. Castillo,

Ricardo García,

Raúl Martínez Bohórquez,

Daniel Morales González,

Yolanda Moreno Salguero,

José Navarro Garmendia,

Scientific Committee:

Fernando Albiac,

Jesús M. F. Castillo,

Gilles Godefroy,

Beata Randrianantoanina,

Local Staff:

Álvaro Iglesias Cambero

Pedro Martín Jiménez

Emmanuel Moreno Mejía

Jorge Rovira Pérez

Marina Polo Rodríguez

Pablo Torrado López

Speakers

Fernando Albiac

Universidad Pública de Navarra, España

Topics and beyond, mathematics and friendship with Nigel Kalton

José Luis Ansorena

Universidad de la Rioja, España

Lipschitz free spaces in the Kalton zone

Florent Baudier

Texas A&M University, USA

The Kalton program

(Online conference)

Bruno M. Braga

IMPA, Brasil

On homeomorphisms between the spheres of ℓk and ℓ2k

(Online conference)

Félix Cabello Sánchez

Inst. Mat. Univ. Extremadura (IMUEX), España

The Serre closure of Banach spaces

Jesús M.F. Castillo

Inst. Mat. Univ. Extremadura (IMUEX), España

Painted from memory

Willian H.G. Corrêa

Universidade de São Paulo, Brasil

Twisted Hilbert spaces not isomorphic to their duals

Willian H.G. Corrêa

Universidade de São Paulo, Brasil

Two steps into the homology of ℓ2

Wilson Cuellar

Universidade de São Paulo, Brasil

About algebras of operators on Z2

Audrey Fovelle

Texas A&M University, USA

The asymptotic Enflo problem

Gilles Lancien

Université de Franche-Comté, France

Nonlinear embeddings and asymptotic geometry of Banach spaces

Raúl Pino

Universidad de Oviedo, España

Rochberg spaces as generalized Z2

Grzegorz Plebanek

Uniwersytet Wrocławski, Polska

Twisted sums with c0 and the CCKY problem

Noé de Rancourt

Université de Lille, France

Ergodicity of the Kalton-Peck space

Beata Randrianantoanina

Miami University, USA

Nonlinear type and metric embeddings of lamplighter metric spaces

Peter Scholze

Universität Bonn, Deutschland

Liquid functional analysis

(Online conference)

Pedro Tradacete

ICMAT, España

Progress in Banach lattices

Participants

Confirmed Participants

Fernando Albiac, Universidad Pública de Navarra, España
José Luis Ansorena, Universidad de la Rioja, España
Antonio Avilés López, Universidad de Murcia, España
Florent Baudier, Texas A&M University, USA
Glenier Bello, Universidad de Zaragoza, España
Bruno M. Braga, IMPA, Brasil
Félix Cabello Sánchez, IMUEX, España
Javier Cabello Sánchez, IMUEX, España
Giulia Cardoso Fantato, Instituto de Matemática e Estatística da Universidade de São Paulo, Brasil
Jesús M.F. Castillo, IMUEX, España
Willian H.G. Corrêa, Universidade de São Paulo, Brasil
Wilson Cuellar, Universidade de São Paulo, Brasil
Valentin Ferenczi, Universidade de São Paulo, Brasil
Audrey Fovelle, Texas A&M University, USA
Ricardo García, IMUEX, España
Gilles Godefroy, Inst. Mat. Jussieu (IMJ), France
Álvaro Iglesias Cambero, IMUEX, España
María Ángeles Japón, Instituto de Matemáticas de la Universidad de Sevilla (IMUS), España
Javier Laguna Ricart, Universidad de Murcia, España
Gilles Lancien, Université de Franche-Comté, France
Pedro Martín Jiménez, IMUEX, España
Raúl Martínez Bohórquez, IMUEX, España
Sofya S. Masharipova, University of Pittsburgh at Johnstown, PA, USA (UPJ)
Daniel Morales González, IMUEX, España
Emmanuel Moreno Mejía, IMUEX, España
Yolanda Moreno Salguero, IMUEX, España
David Muñoz Lahoz, Universidad Autónoma de Madrid, España
José Navarro Garmendia, IMUEX, España
Raúl Pino, Universidad de Oviedo, España
Grzegorz Plebanek, Uniwersytet Wrocławski, Polska
Marina Polo Rodríguez, IMUEX, España
Noé de Rancourt, Université de Lille, France
Beata Randrianantoanina, Miami University, USA
Jorge Rovira Pérez, IMUEX, España
Peter Scholze, Universität Bonn, Deutschland
Pablo Torrado López, IMUEX, España
Pedro Tradacete, ICMAT, España
Shukhrat M. Usmanov, University of Pittsburgh at Johnstown, PA, USA (UPJ)

Pre-registered

Eugene Bilokopytov, ICMAT, España
Siham Hachoum, Hassan 2 University of Casablanca, Morocco
Wiesław Kubiś, Institute of Mathematics, Czech Academy of Sciences, Czech Republic
Florence Lancien, Université Marie et Louis Pasteur, France

Program

09:15 - 09:30

Registration and Opening

Welcome

09:30 - 09:55

Fernando Albiac

Topics and beyond, mathematics and friendship with Nigel Kalton

10:05 - 10:50

Grzegorz Plebanek

Twisted sums with c0 and the CCKY problem

10:50 - 11:15

Coffee break

11:15 - 12:00

Peter Scholze (Online)

Liquid functional analysis

12:05 - 12:50

Willian H.G. Corrêa

Twisted Hilbert spaces not isomorphic to their duals

12:55 - 13:40

Félix Cabello Sánchez

The Serre closure of Banach spaces

14:00

Lunch

09:15 - 09:55

Beata Randrianantoanina

Nonlinear type and metric embeddings of lamplighter metric spaces

10:05 - 10:50

Noé de Rancourt

Ergodicity of the Kalton-Peck space

10:50 - 11:15

Coffee break

11:15 - 12:00

Florent Baudier (Online)

The Kalton program

12:05 - 12:50

Raúl Pino

Rochberg spaces as generalized Z2

12:55 - 13:40

Wilson Cuellar

About algebras of operators on Z2

14:00

Lunch

15:45 - 16:10

María Ángeles Japón

The property M of Kalton, type functions and their applications to fixed point theory

16:15 - 16:40

Eugene Bilokopytov

Von Neumann-Maharam problem for vector lattices

16:45 - 17:10

Sofya S. Masharipova

Non-commutative Lp-spaces associated with real von Neumann algebras (with Shukhrat M. Usmanov, UPJ)

09:30 - 09:55

Jesús M.F. Castillo

Painted from memory

10:05 - 10:50

Willian H.G. Corrêa

Two steps into the homology of ℓ2

10:50 - 11:15

Coffee break

11:15 - 12:00

Bruno M. Braga (Online)

On homeomorphisms between the spheres of ℓk and ℓ2k

12:05 - 12:50

Gilles Lancien

Nonlinear embeddings and asymptotic geometry of Banach spaces

12:55 - 13:40

Audrey Fovelle

The asymptotic Enflo problem

14:00

Lunch

18:30

Tour

21:30

Dinner

09:30 - 09:55

Giulia Cardoso Fantato

Uniform homeomorphisms and interpolation of families of Banach spaces

10:00 - 10:25

David Muñoz Lahoz

Wickstead's conjecture on positive projections and non-representable Banach lattice algebras

10:30 - 10:55

Wiesław Kubiś

Generic operators

11:00 - 11:30

Coffee break

11:30 - 11:55

Antonio Avilés López

Transfinite Daugavet property

12:05 - 12:50

José Luis Ansorena

Lipschitz free spaces in the Kalton zone

12:55 - 13:40

Pedro Tradacete

Progress in Banach lattices

13:45

Closing

Registration

The registration period for this workshop has now closed (deadline: April 30th, 2026).

If you have any questions, please feel free to contact the organizing committee at .

Payment Methods

Registration is opened until April 30th.

Registration is free for invited speakers and for members of the Department of Mathematics at the University of Extremadura.

For other members, there is a registration fee of 200 €. This fee covers lunches, coffee breaks, a tour around Badajoz and the official dinner of Thursday.

There are three available methods to complete your registration payment:

1. Bank Transfer

Please use the following details for the transfer. All bank fees must be covered by the sender to ensure the full registration fee is received.

· IBAN: ES74.0049.6147.63.2210012477

· BIC/SWIFT: BSCHESMMXXX

· Beneficiary name: Universidad de Extremadura (Tax ID: Q0618001B)

· Bank: Banco Santander

· Transfer concept/reference: THE KALTON YEARS + Full Name of Participant

· Transfer amount: 200.00 EUR

2. Credit/Debit Card (Online POS):

You can pay via our online payment gateway (TPV) on the official events page here. The transaction will be processed through the University's Santander account:

· Account Reference: ES68 0049 6147 6729 1001 3180

3. Cash Payment (On-site):

Payment in cash will be accepted at the conference venue.

Important Note: Please be aware that official invoices cannot be issued for cash payments made during the event.

Invoicing and Proof of Payment

To receive a formal invoice, you must request it within 15 days of payment. Please specify whether the invoice should be issued to an institution (University, Institute, Company, etc.) or to the individual participant. In both cases, a proof of payment is required. Please send your request to kaltonyears@gmail.com with the following details:

· Tax Name: (Full name of the individual or the Institution).

· Tax ID: (NIF, CIF, or VAT Number).

· Full Billing Address: (Including city, postal code, and country).

Universidad de Extremadura Instituto de Matemáticas UEx Departamento de Matemáticas Concejalía de Turismo de Badajoz

Ayuda a Grupos GR24056 y Proyecto de investigación IB24002

UE

Proyecto PID2023-146505NB-C21 financiado por MCIU/AEI/10.13039/5011000110331 y por el FEDER/UE.

MCIU_AEI_UE

Practical Information

Related Conference in France - Banach Spaces and Their Operators

May 4–7 2026 · France

Two weeks before our workshop, the conference Banach Spaces and Their Operators will take place at Lille, France (May 4th-7th, 2026). Participants planning to attend both events may wish to arrange travel from France to Badajoz directly.

More information: https://www.mathconf.org/bsto2026

Accommodation in Badajoz

We suggest the following hotels:

    • Hotel Río Badajoz ★★★
      Address: Avenida Adolfo Díaz Ambrona, 13, 06006 Badajoz
      • Premium Double Room — Single use (DUI): 74,00 €/night (VAT incl.)
      • Premium Double Room — 2 beds: 79,00 €/night (VAT incl.)
      • Buffet breakfast (optional): 8,00 €/person (VAT incl.)
      • Parking: 9,00 €/day
      Booking: Send an email to hola@orexco.net
      Cancellation policy: Free cancellation up to 72 hours before arrival. After this period, the first night will be charged.
      Check-in: from 14:00
    • Hotel Tres Campanas ★★★★
      Address: Calle Duque de San German, 6, 06001 Badajoz
      • Promotional code: CONUEX26
      • Applicable only to bookings made through the website
      • Subject to availability at the time of booking
      Cancellation policy: Free cancellation up to 48 hours before arrival. After this period or in case of no-show, one night will be charged.
    • Hotel Badajoz Center ★★★★
      Address: Avenida Damián Téllez Lafuente, 15, 06010 Badajoz
      • Promotional code: THEKALTONYEARS
      • Discount: 5% off the best available rate
      Payment and cancellation policy: According to the hotel's website conditions.
    • Sercotel Gran Hotel Zurbarán ★★★★
      Address: Calle Gómez de Solís, 1, 06001 Badajoz
      • Promotional code: THEKALTON2026
      • Discount: additional 5% off the best available online rate at the time of booking
      • Code valid until 01/05/2026
    • Hotel Turia Badajoz ★★★★
      Address: Avenida Augusto Vázquez, 2, 06006 Badajoz
      Website: turiahotels.es
      • Promotional code: OREXCO (for bookings made through the hotel's website)
      • The discount is applied to the rates available at the time of booking
      Payment policy: Payment upon arrival at the hotel. Credit card required only as a guarantee.
      Cancellation policy: Free cancellation until 00:00 on the day before arrival. After this period, 100% of the reservation amount will be charged. Also applicable in case of no-show or early departure.

Getting to Badajoz

  • By plane: The nearest airports are Badajoz Airport (BJZ) — 15 min from the city — or Seville (SVQ) (~180 km) and Lisbon (LIS) (~240 km), both with regular bus/car connections.
  • By train: Badajoz is served by Renfe with connections to Madrid, Cáceres and Mérida. renfe.com
  • By bus: Regular long-distance coaches operate between Badajoz and Madrid, Lisbon, Seville and other cities. alsa.com
  • By car: Badajoz is located on the A-5 motorway (Madrid–Lisbon corridor), approx. 4 h from Madrid and 2.5 h from Lisbon.
  • From France: A popular route is Bordeaux → San Sebastián → Madrid → Badajoz (A-5).

View venue on Google Maps

Badajoz is a historic city on the banks of the Guadiana river, at the border between Spain and Portugal. Extremadura, its region, is home to two UNESCO World Heritage Sites: the walled old city of Cáceres (90 km) and Mérida (60 km), the best-preserved Roman city in Spain and the ancient capital of Lusitania.

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About This Image

This outstanding image is a slightly modified version of a drawing by the great artist Jill Thompson reimagining the myth of Orpheus. The image appears as panel 1 in p.4 of volumen 7, Brief Lives, of The Sandman, by Neil Gaiman, published by Vertigo/DC comics. The reproduction here is for non-commercial purposes and has been chosen for the workshop because of its quality and many meanings derived from the Brief Lives story.

Orpheus is a foundational myth in western culture. An extraordinarily gifted being (the singing of Orpheus was even able to move Hades and Persephone to tears). Maybe for that reason the Kindly Ones chased him and only let his head floating in the river. Neil Gaiman continues the history: a millenary order rescued the head and has kept it in custody to this day. Brief Lives begins with Andros, the current guardian, thinking: It is a miracle, of course. The miracle is, of course, to have been even near such an extraordinary talent.