## Making MaRDI Gallery

You want to know who is making MaRDI and what motivates them? Here we introduce you to the people who shape MaRDI with their expertise and vision for mathematical research data. Every two weeks another interview will be published here.

Statistics and Machine Learning

**Who are you in two sentences?**

I am a statistical consultant and lecturer at TUM. In MaRDI I am part of the Task Area Statistics and Machine Learning and a member of the Council.

**In which field of mathematics do you work and how long have you been working there?**

I studied financial mathematics with a focus on statistics and probability. During my PhD, which I completed in 2007, I worked mainly with time series data. I developed new models, but also did applied work in implementing algorithms needed for inference in these models. Today I would say I am concerned with modelling dependencies in a broader sense.

**What is the most important problem in your field that MaRDI aims to solve?**

It is always necessary to analyze new methods/algorithms in a simulation study. But the actual effectiveness/relevance of the method is of course best described when applied to real world data. Our goal is to help make such data available based on FAIR principles. This will be exemplified by the creation of a library of data sets that can be used in the graphical modeling framework. Some of these data sets can be classified as extremely useful because there is also something like a ground truth for these data. The ground truth describes the true relationships between the variables of the dataset based on external information, such as expert knowledge.

**What question can you answer best regarding MaRDI/ What's your expertise within MaRDI?**

I am always unsure about the things I know. That's why it's not so easy to say. I would guess that it has to do with making statistical analyses reproducible

**How do you wish the data culture to change with the help of MaRDI?**

I think there is also room for improvement regarding the data culture in the statistics community. But I would like to see much more awareness in other scientific fields that the code of a statistical analysis is research data, which should be treated according to FAIR principles.

**How would you describe a typical work day?**

Very often it is a mixture of teaching and consulting. Most of the teaching now takes place in person again. Since TUM is quite widely scattered, this also means a certain amount of travel. Consulting, on the other hand, takes place relatively exclusively online. So a typical workday also includes an online meeting.

**What is an aspect of your work that you particularly enjoy and what is one that you find challenging?**

Within statistical consulting, I meet many different people. I get an insight into their problems, which is very interesting, and the opportunity to help them solve them. I enjoy seeing them realize what the solution to the problem might be. The same is true, of course, of the moments when students understand connections that you have tried to explain to them. Right now it's exam time, and I have to say that grading is one of the more challenging tasks. Maybe not challenging, but definitely less joyful.

*March 21, 2023*

TA3: Statistics and Machine Learning

Technical University of Munich

**Do you have a favorite place you go to for thinking about a problem?**

No, that is not the case. I try to take advantage of every opportunity.

**What do you enjoy outside work?**

My family and hockey. In winter I play ice hockey and the rest of the year inline hockey.

Computer Algebra

**Who are you in two sentences?**

I am an algebraic geometer who loves to program. I am very curious about all the ramifications of using software for algebraic geometry research and for pure mathematics in general.

**In which field of mathematics do you work and how long have you been working there?**

Originally, I come from algebraic geometry and computer algebra. Since I started working at TU my focus has shifted towards discrete geometry and combinatorics. I have always found it useful to automate my paper and pencil calculations, and I used the computer to verify or disprove my conjectures on large example classes.

**What is the most important problem in your field that MaRDI aims to solve?**

Reproducibility. The topic of mathematical papers aided by computer but missing the code and other documentation for reproducing the computer aided part also comes up in several of the other interviews. I want to add some positive examples. We know of several experiments that measured the Earths circumference (Eratosthenes), the distance from the Earth to the sun (Aristarchus of Samos), or to the moon (Hipparchus), that happened in the antiquity. We not only know the results but also details on how these researchers arrived at their results. We can reproduce them. That is an amazing thing in my opinion that after more than two millenia the details of these experiments are still so well-preserved that we can arrive at the same results and verify correctness of the procedures.

We have detailed knowledge about the arc measurement expedition of Delambre and Méchain in 1792–1798, to know exactly where they made a mistake, that made the prototype metre bar 200 micrometers too short. It was intended to define the length of a meter such that the Earths polar circumference is exactly 40'000km. Instead we now have 40'008km. But we can reproduce this error, we have documentation to know where it came from.

In these times, before computers and large scale cheap printing, it was much harder to publish anything, to make it widely known, to preserve it for the future. Today the scientific community is much larger, computers and the internet have made publishing almost instant, many platforms allow long-term archival, and nevertheless there are papers that are not reproducible the instance they get published, just because they lack the accompanying code and documentation.

**What's your expertise within MaRDI?**

I have worked with mathematical software for a long time, while also working with mathematics and mathematicians, especially from pure mathematical fields. Very often I have acted as a bridge between my mathematical colleagues and the computer. Hence, I know what documentation and other material mathematicians need to reproduce experiments on their machine.

**How do you wish the data culture to change with the help of MaRDI?**

I hope to make the entire community more aware of the challenges posed by working with computers in mathematics, in particular reproducibility of mathematical results. Due diligence requires time and effort. But it will almost immediately increase the quality of research. Duplicate work and errors will be avoided.

**How would you describe a typical work day?**

Every day is different. Sometimes I have time to read papers or program a lot. Other times I have many meetings to attend or I travel to conferences and workshops. The only constant is that my todo list keeps getting longer.

**What is an aspect of your work that you particularly enjoy and what is one that you find challenging?**

I enjoy very much talking about topics that I am passionate about, like reproducibility, automatization and standardization. Since MaRDI and NFDI are quite large, sometimes everything seems to happen at once which can be quite stressful.

*March 07, 2023*

TA1: Computer Algebra

Technische Untversität, Berlin

**Do you have a favorite place you go to for thinking about a problem?**

I have many brilliant colleagues. Usually it helps me to explain my problem to one of them. If it does not go away on its own by the end of my explanation, my colleagues will solve it.

**What do you enjoy outside work?**

I like to go climbing (bouldering) and to spend time with my kids.

Data Culture and Community Integration

**Who are you in two sentences?**

I am MaRDI's Mathematical Data Consultant and my job is to help people find answers to all research-data questions they might have. I love to be in contact with the community and to make everyday tasks more efficient. That my own academic research experience can be of use here is a big plus for me.

**In which field of mathematics do you work and how long have you been working there?**

My background is in maths and statistics, I did my diploma in Karlsruhe and my PhD at Warwick in the UK. I came back to Germany roughly six years ago to work in Leipzig, mostly with Bernd Sturmfels' non-linear algebra group.

**What is the most important problem in your field that MaRDI aims to solve?**

That would be reusability, I guess. I used to sometimes struggle to access the final print version of my own articles, and sometimes couldn't get a couple of lines of code to run which worked just fine half a year earlier. If I struggle to do that in order to build on my own past research, how can I expect others to be able to reuse and enhance these results?

**What question can you answer best regarding MaRDI/ What's your expertise within MaRDI?**

I have a very central position in MaRDI. Thanks to fortnightly and monthly updates with all the other task areas and their assigned representatives, I have a very broad picture of what everyone is up to. So if you have any query, I can probably find the expert within MaRDI to answer that. Also I already gained a lot of practice in speaking about MaRDI in general and about the role repositories play in sustainable research-data management.

**How do you wish the data culture to change with the help of MaRDI?**

I wish researchers would feel free to take their time to do all the 'extra work' surrounding their articles: polishing code, providing small working examples to very complex theories, thinking about long-term storage and good documentation. MaRDI's efforts will raise awareness of the benefits of such tasks and will hopefully, in the long term, make people value these efforts appropriately.

**How would you describe a typical work day?**

It's part organisation, part looking into technical details other people work on, part reading and talking to people, and part publishing articles and presenting MaRDI at events. Right now I mainly focus on preparing the first lecture on mathematical research-data management.

**What is an aspect of your work that you particularly enjoy and what is one that you find challenging?**

What I enjoy most is talking to people, and I find it challenging that much of this happens online rather than face to face. It's being in close contact with the mathematical community and finding solutions for their tiny everyday hurdles that keeps me going.

*February 14, 2023*

TA6: Data Culture and Community Integration

Universität Leipzig

+49 341 9732183

goergen@mardi4nfdi.de

**Do you have a favorite place you go to for thinking about a problem?**

Leipzig is surrounded by beautiful lakes and woods, I like to go there in all weathers to watch and enjoy nature. Thinking and finding solutions for me happens mostly unconsciously in those environments.

**What do you enjoy outside work?**

I love my garden and my dog, so I spend lots of time outdoors with both. Indoors I enjoy game nights and long chats with friends.

Cooperation with Other Disciplines

**Who are you in two sentences?**

I am Anita Schöbel, professor for Applied Mathematics and director of the Fraunhofer Institute for Industrial Mathematics (ITWM). Besides I am an enthusiast promoting mathematics for solving problems that are real and matter.

**In which field of mathematics do you work and how long have you been working there?**

I am working in the field of optimization, mostly in discrete, multi-objective, and robust optimization. I love applications and have been studying optimization of public transport for more than 20 years. This requires not only sound knowledge of mathematical optimization but also of the application domain.

**What is the most important problem in your field that MaRDI aims to solve?**

Bringing together different disciplines which is only possible if we speak the same (scientific) language, use the same ontologies and are able to interchange data.

**What's your expertise within MaRDI?**

I provide case studies and many years of experience with interdisciplinary work including classification of models and data between disciplines.

**How do you wish the data culture to change with the help of MaRDI?**

That's an easy question: the data culture should be FAIR. I also hope that MaRDI contributes to the aim that working with data, providing datasets and classifying and transforming data will be higher valued by the research community.

**How would you describe a typical work day?**

Meeting, meeting, meeting, maybe lecture, meeting, meeting, meeting. And during all the day e-mails are floating into my mailbox happily waiting for me to answer them.

I greatly enjoy contributing to the impact, mathematics does have in the real world. I also enjoy working together with many very engaged researchers. It is a challenge to find time for everything I would like to do.

*January 31, 2023; Photo: © Fraunhofer ITWM*

TA4: Cooperation with Other Disciplines

Fraunhofer Institute for Industrial Mathematics (ITWM), Kaiserslautern

anita.schoebel@itwm.fraunhofer.de

**Do you have a favorite place you go to for thinking about a problem?**

Sure! The Palatinate forest.

**What do you enjoy outside work?**

Meeting family and friends, hiking, biking, nice restaurants, and certainly (Palatinate) wine.

The MaRDI Portal

**Who are you in two sentences?**

I'm Johannes Stegmüller, I am a researcher and software developer with a technical computer science background. My journey brought me from creating devices on the hardware level to working on something which takes place mostly in the web.

**In which field in MaRDI do you work, and how long have you been working there?**

I'm working on the MaRDI Portal since the beginning of 2022. My focus is the processing of formulas in the MediaWiki/Wikibase environment used on the Portal.

**What is the most important problem in your field that MaRDI aims to solve?**

Mathematical research data is distributed over various infrastructures and stored there in a silo-like fashion. The MaRDI Portal will be a central public endpoint for finding and accessing this distributed data.

**What question can you answer best regarding MaRDI?**

Questions regarding the database and search index creation of the formula search in MaRDI Portal. I'm currently gathering knowledge in the computer-aided processing of various formula notations.

**How do you wish the data culture to change with the help of MaRDI?**

I wish through MaRDI a fruitful collaboration can be established between the participating institutes. I wish the created infrastructure and measures to accomplish FAIR research data culture are still in use long after they were created.

**How would you describe a typical work day?**

First, I collect all possible relevant thoughts and ideas. Write them down in a digital document. To then structure and logically align them. I make my computer understand these writings and translate them into its own language. Transfer them to a global swarm of computation instances. Finally, somewhere comes a cryptic message that tests failing because the software deployment is missing a semicolon.

**What is an aspect of your work that you particularly enjoy, and what is one that you find challenging?**

I really enjoy learning in a new environment and to have a focus on creating open-source computer systems which are helping a vast user base. Not being a mathematician, it is a challenge to gain a profound understanding of some of the more complex formulas handled by the tools developed.

**What are your ideas for MaRDI?**

Creating a software which automatically produces a minimalistic written publication from arbitrary research (meta)data or software source code. This would enable to place a findable and citable record of the publication on most research data infrastructures.

*January 19, 2023*

TA5: The MaRDI Portal

FIZ Karlsruhe

johannes.stegmueller@fiz-karlsruhe.de

**Do you have a favorite place you go to for thinking about a problem?**

Any places that have a far sight, like towers, mountains etc.

**What do you enjoy outside work?**

Riding the bike, hitchhiking and editing audio. An early moment where I realized that math really makes a difference was the feasibility to create a spectrogram from an audio signal using the Fourier transform.

Computer Algebra

**Who are you in two sentences?**

I am an arithmetic geometer, which means I am interested in the area of mathematics where number theory and algebraic geometry intersect. For MaRDI I am responsible for trying to introduce some kind of software peer reviewing process for mathematical papers that contain software components.

**In which field of mathematics do you work and how long have you been working there?**

I studied Mathematics at the university of Utrecht after which I did my PhD at Ulm University. I’m currently working as a postdoc in Kaiserslautern. I specialize in algorithmic arithmetic geometry and besides doing research I’m also help out with developing the computer algebra package OSCAR.

**What is the most important problem in your field that MaRDI aims to solve?**

One very big issue in computer algebra in general is that writing software is mostly seen as an afterthought. The mathematical paper that gets published is the important thing and the software is just… there. This attitude causes a multitude of problems. Whenever a paper that contains a software component gets sent to a journal, the reviewers check the paper, but the code often gets ignored. But this is kind of ridiculous. You wouldn’t believe the statement of a theorem without a proof, so why would you blindly believe a result that is partially based on computations without checking the code?

There are also issues with proper acknowledgment and citations. It happens far too often that people reuse code without properly crediting the author. I also know of some very smart and talented mathematicians who chose to mostly work on developing computer algebra software, who were forced out of academia. They didn’t have enough publications, so they couldn’t get a job. But what they did definitely wasn’t trivial. It required a very deep knowledge of both mathematics and writing efficient low level C code. Writing this kind of software is far more difficult than writing a decent paper. But it simply doesn’t get acknowledged as such.

**What's your expertise within MaRDI?**

I’m involved in trying to improve the software peer reviewing process in MaRDI. For that I give talks about why it is important and I reach out to journals and conferences to try to develop standards that can be used in the future.

**How do you wish the data culture to change with the help of MaRDI?**

I hope that people will slowly start to see data and algorithms as vital parts of a publication. When people start treating software and data with more care and attention and also acknowledge the effort that goes into it, they will make more of an effort to make it available for peers to look at and reuse. Something which is important for the future of mathematics as a whole.

**How would you describe a typical work day?**

It really depends on the day. Some days I’m just sitting behind my computer the entire day programming to get some algorithms into OSCAR, other days I’m mostly reading papers and doing research.

I also spend time approaching editors and organizers of conferences to talk about implementing software peer reviewing. In the future I’m going to test out the ideas that we have and I’ll probably spend a lot of time reviewing software.

Research-wise I simply like learning new parts of mathematics and having a deeper understanding how everything is interconnected. I also always quite enjoy teaching (although I don’t always have teaching responsibilities).

One of the most challenging things is trying to get community acceptance of software peer reviewing. Most people who have worked with software before understand that it is necessary. But doing it properly means putting in extra work and that costs time. And there is so much pressure on researchers to keep publishing papers that there is simply not always enough time to handle the software components with care. There is also a bit of politics involved here. Because systems and storage solutions for the better treatment of software and data need to be put into place if we want to improve things, but that costs a lot of money.

*January 03, 2023*

TA1: Computer Algebra

Technische Universität Kaiserslautern

hanselman@mathematik.uni-kl.de

**Do you have a favorite place you go to for thinking about a problem?**

A bit of a boring answer, but I think I work best sitting behind my desk. Either in my office at the university or at home.

**What do you enjoy outside work?**

I enjoy ballroom dancing (Latin and standard), I like cooking, playing board games, playing video games, drawing and I also go hiking from time to time.

Data Culture and Community Integration

**Who are you in two sentences? **

After graduating in theoretical physics, I switched to pure math for good; and after spending many years in Berlin, I became a professor of differential geometry at Philipps-Universität Marburg in 2008. Right now, I am also president of the German Mathematical Society DMV (Deutsche Mathematiker-Vereinigung), a really challenging and exciting (side) job!

**In which field of mathematics do you work and how long have you been working there?**

When I was in my third semester, I fell mathematically in love: I attended a summer school on Lie groups and representation theory, and I thought: Yes, this is what I want to do for the rest of my mathematical life. Just as in real life, it didn’t turn out exactly like that, but it’s coming close: Since many years, I am using Lie theory successfully for solving problems in differential geometry. My research deals with the interplay between solutions to geometric differential equations like the Dirac equation, the holonomy theory of connections, and manifolds with additional structure, like certain curvature conditions or the existence of a compatible almost hermitian structure. Symmetries are everywhere and Lie groups are the means to describe them!

**What is the most important problem in your field that MaRDI aims to solve?**

Lie theory and its applications to differential geometry can be very computational - but we, as a community, are not data specialists. I hope that MaRDI will help in professionalizing the documentation of our findings. From Spring 2023, I will be dealing with another challenge: Our project Math4VIP (= Visually Impaired People) was approved a few weeks ago by the VolkswagenStiftung. The goal of the Math4VIP project is to create a central platform that provides information about and access to mathematics and how mathematical content should be prepared for students with visual impairment. In this process, new standards will be developed, materials will be created according to these standards, guidelines will be written and publicized through appropriate outreach. In this way, students with visual impairment have access to barrier-free materials, regardless of the university at which they study. Some of this sounds familiar, doesn’t it?

**What's your expertise within MaRDI?**

I’m afraid my expertise is less on the technical side - my role in MaRDI as DMV president is to act as a link to the mathematical community as a whole, to make contacts and bring together lose ends.

**How do you wish the data culture to change with the help of MaRDI? **

It should become second nature to all mathematicians to implement and adhere to a data culture adapted to their research area in their daily work.

**How would you describe a typical work day?**

It starts as it ends - with reading and replying to dozens of emails (happily, my „digital secretary“ is doing a good job - supported by some AI hidden in the software). In between, I give lectures, I work with my students and collaborators, and I deal with the infinitely many aspects of university administration. All in all, the days are way too short.

I appreciate very much working with and meeting people from many different countries. I do believe that scientific exchange is a contribution to international understanding, for which there is the beautiful German word „Völkerverständigung“. I also enjoy the freedom that our profession gives to us (sometimes, we forget about it). What I find very challenging is the increasing heterogeneity of the student community and the many blanks they have when entering university.

*December 20, 2022; Photo: © Thomas Richter*

TA6: Data Culture and Community Integration

Philipps-Universität Marburg

agricola@mathematik.uni-marburg.de

**Do you have a favorite place you go to for thinking about a problem?**

Conferences and seminars! When I listen to other people talking about math, my mathematical brain speeds up automatically, whether the topic is interesting or not. I get new ideas, I take lots of notes, and sometimes, I do a calculation or some reading on the side.

**What do you enjoy outside work?**

Singing, reading, and travelling. I am a tenor in a Marburg choire, I read dozens of books every year (Robert Harris is one of my favourite authors), and I am REALLY looking forward to a trip to the Falkland Islands that my partner and I will do over Christmas and New Year! Let’s see how penguins and sea lions will celebrate this…

Data Culture and Community Integration

**Who are you in two sentences?**

I am a trained mathematician, I really enjoy bringing people together and I like to organize events. I am happy to combine these in my job as MaRDI's Dissemination Coordinator.

**In which field of mathematics do you work and how long have you been working there?**

I studied mathematics at the University of Leipzig, where I specialized in functional analysis and wrote my diploma thesis in ergodic theory. Since working for MaRDI at the Max Planck Institute in Leipzig, I have been more engaged in algebraic statistics and am involved in a research project in this area.

**What is the most important problem in your field that MaRDI aims to solve?**

Since I am quite new to mathematical research, so I am sharing from this point of view. I know the feeling of being overwhelmed by all the material I can look at and try out. This applies to books and papers as well as software and code snippets I don't understand exactly what they do. If these things are provided with good metadata and instructions it will be easier, not only for newbies like me, to get into research and not spend too much time on the on tinkering around. For example, I'm busy right now getting a piece of software up and running.

**What question can you answer best regarding MaRDI?**

As MaRDI's Dissemination Coordinator I am up to date with everything that happens in MaRDI disseminationwise. In particular which and what sort MaRDI events and actions are planned, what's happening in each task area.

**How do you wish the data culture to change with the help of MaRDI?**

In an ideal world every mathematician would have heard about the FAIR principles and would have access to knowledge and infrastructure to follow these. It would be natural to publish all data associated with a paper and also research data for example software would be recognized as a scientific achievement by itself. By rising awareness, creating a central portal, offering workshops and engaging in technical peer review MaRDI can help with these changes.

**How would you describe a typical work day?**

My job is very multifaceted. I have organizational and administrative tasks. I plan events and have conversations and meetings with people inside and outside MaRDI, including libraries, which are also a target group of MaRDI.

To experience the handling of mathematical research data first hand, I am involved in a research project in algebraic statistics. In this project we create a database of mathematical objects, namely Conditional Independence Structures.

I also travel frequently, both to MaRDI workshops and to other events at which I represent MaRDI.

I enjoy learning so many new things during my work, as I come in contact with many different areas and people in mathematics. In addition, it is exciting to accompany a project in its initial phase, in which all the structures are only just being created.

I find it challenging to get people excited about research-data management and to show them that it is worthwhile doing, even if it requires a lot more work at first.

November 22, 2022

TA6: Data Culture and Community Integration

Max Planck Institute for Mathematics in the Sciences (MPI MIS), Leipzig

+49 341 9959705

bacher@mardi4nfdi.de

**Do you have a favorite place you go to for thinking about a problem?**

The best way for me to think is to go for a walk. The parks in and the forests around Leipzig are ideal for doing so.

**What do you enjoy outside work?**

I like to organize events in my free time, too; ranging from Acroyoga festivals to board game nights. And I like to work with my hands: gardening, pottery, cooking, ...

Governance and Consortium Management

**Who are you in two sentences?**

I am a physicist by training and a scientist at heart. I guess I have some capabilities in analysing things and in working with people.

**In which field of mathematics do you work and how long have you been working there?**

Most of my work is interdisciplinary in nature; at the bridge between statistics und biomedical sciences.

**What is the most important problem in your field that MaRDI aims to solve?**

Data from the biomedical sciences is usually well-organized and described, and is nearly fully FAIR. However, as somebody who develops methods, I often struggle to transfer the knowledge about this data that would allow me to develop appropriate methods for data handling. I would like to see MaRDI make this process easier including the access to the available methodologies.

**What question can you answer best regarding MaRDI/ What's your expertise within MaRDI?**

Together with Thomas (Koprucki), we had the early concept for MaRDI, when there was not even the notion of NFDI. So, I think and hope, that I can and will contribute to the conceptual development of MaRDI as a whole.

**How do you wish the data culture to change with the help of MaRDI?**

Data is our treasure and source of knowledge. So I would like to see this treasure to be lifted and the researcher who provides it, to give the appropriate credits.

**How would you describe a typical work day?**

I usually start checking emails (which is almost always a bad idea but keeps me aware of the things ahead), I take a walk or a ride by bike (to office) and start with my bullet journal to do the morning reflection (If I drop this, I know, this will be one of these days...). I am in a lot of meetings with different people on different topics. In between I try to work on a paper or some other content. I usually need a break in the late afternoon before continuing. I often do some planning for new things or just clearing the leftovers in the evening.

I like to learn new things from all areas of science, to combine knowledge on a path to ... my tiny bit of wisdom. I find it challenging, that teams always struggle to define their processes of working.

November 08, 2022; Photo: © Verena Brandt

TA7: Governance and Consortium Management

TA4: Cooperation with Other Disciplines

TA3: Statistics and Machine Learning

Weierstrass Institute for Applied Analysis and Stochastics (WIAS), Berlin

+49 30 20372564

karsten.tabelow@mardi4nfdi.de

**Do you have a favorite place you go to for thinking about a problem?**

When I am on route, either by bike or on foot.

**What do you enjoy outside work?**

I like to play the piano and to sing, I like hiking in the mountains, cooking and eating. I also like to think about politics and all disciplines of science.