Definitely Maths!


In our fast online world, where things can be outdated within a day, stability can be found in mathematical theorems. This mathematical foundation cannot be ignored. It is the basis for calculations by all engineers. What Pythagoras proved to be true over 2,000 years ago, is still true today.

“That’s why I love delving into math history and browsing through old books”, says Klaas Pieter Hart, associate professor at the department of Mathematics in Delft. “I want to read original works without any interpretational filters by a modern author. Lose yourself in a library and let serendipity do its work. You will find unexpected ideas by known and unknown mathematicians who proved a theory 300 years ago that still stands today for the entire field of mathematics. I am convinced that there is so much material and so many theorems left uncovered,  that one person or even a whole team could not comprehend in a lifetime.”

Mathematics is the basis for calculations of all engineers

“That is why I am not always pleased with the growing amount of online information. A lot of works are now available as scans, but they are often incomplete. My favourite providers are Göttingen University (Germany) and Gallica (France), who try to be complete and deliver on quality. Their online material makes it easier to search for particular authors or terms. However, online you often run into barriers of subscriptions to journals before you can have access. TU Delft  Library is a great help with finding and delivering material to me. I just need to be patient before my scan or hardcopy is delivered. That’s why I’m still the kind of person who likes to have books around. Knowledge nearby on a shelf. Of course there is a financial consideration to what can be offered both in the online and offline collection. For me, the best subscriptions to math database are: MathSciNet: and Zentralblatt: They contain the most valuable publications for all mathematicians. If they were ever up for discussion to be removed from the collection, I’d be up in arms, and not only I.”


Topology – coffee cups and donuts

Klaas Pieter is equally passionate about his field of interest within mathematics: general and set-theoretic topology, which is all about defining the properties of polish-circlespace and objects. “Within topology you can argue that a coffee cup and a donut have the same properties, i.e. a hole in the middle”, Klaas Pieter explains. “You can prove this by a clear and pure mathematical formulation of what a hole is exactly. If the coffee cup was made of flexible material, you could deform it into a ring-shape without tearing it or even punching in it. You could bend all the material that forms the cup around the handle. And there you have it. On first sight the two objects might not be seen as the same, but mathematically they fall under the same definition. Similarly, a curve and a straight line can be defined as part of the same set. The notion of `curve’ may seem clear intuitively  (straight or squiggly line), but its proper mathematical definition (one-dimensional continuum) allows for many counterintuitive examples, such as the polish circle, featured here on the right.


The mathematical foundation, however abstract, is entwined in everything around us. It links the past and the present, online and offline”

Want to read about Klaas Pieter’s work on topology? Have a look in his favourite databases:

Library Information Box

There is something to be said about seeing racks upon racks and while walking through the library and smelling the paper filled with good reading.

Nevertheless a physical collections cannot to be compared with the benefits of online access.

Online journals and books are available 24 hours a day, 7 days a week and you have the comfort of reading it where ever you may be and by anyone with access to computer with a working internet connection.

The online subscriptions can be used by multiple users at the same time. So, no waiting list, the information is just a few clicks a way.

The strategical goals of TU Delft Library are to create a scientific collection that is relevant to support of research and education of TU Delft. In the coming years the faculties of the Technical University will be invited to discuss the future of the Library collections in the most broad sense of the word.

More information

Klaas Pieter Hart– Faculty of Electrical Engineering, Mathematics and Computer Science

Author: Marieke Hopley – TU Delft Library

Photography: Marcel Krijger –

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