## Updated Edition of Introduction of Wittgenstein’s Tractatus Logico-Philosophicus

During the past several months we worked on a German edition of the book* Introduction of Wittgenstein’s Tractatus Logico-Philosophicus *by F. Hülster. During that process we decided to update the existing English version so that it would be in full agreement with the upcoming German edition. At the same time, we corrected some minor errors. That updating effort of the English version is now complete, and the updated edition is available.

## Circular slide rule based on Bürgi’s Logarithm Tables of 1620

The book *The Construction of Mathematics: The Human Mind’s Greatest Achievement* includes creation of tables of the logarithm function by the Swiss craftsman, engineer, and mathematician Jost Bürgi around 1600 CE, with delayed publication in 1620. The book includes the title page of Bürgi’s tables, then explains that the black numbers of the inner ring are on a logarithmic scale.

Due to that feature, two copies of that ring of numbers can be arranged in nested fashion depict a circular slide rule.

Bürgi did not realize this, or rather, there is no evidence that he did. Instead, William Oughtred invented the circular slide rule two years later, in 1622.

We couldn’t rest until we had implemented the circular slide rule based on Bürgi’s title page. For an authentic look, we created with Photoshop two differently sized copies of the black ring of numbers of Bürgi’s title page. The resulting rings were encased in Lexan and connected by a center bolt. It is fun to multiply and divide numbers by rotating the inner, smaller disk, all the time thinking that this is based on the work of genius done almost 400 years ago.

## Updated edition of book The Construction of Mathematics

A few readers of the book *The Construction of Mathematics: The Human Mind’s Greatest Achievement *had suggested that the discussion of Wittgenstein’s approach for the resolution of philosophical questions, which is central to the arguments of the book, be expanded. The updated edition released in January 2018 contains the desired additional explanations. At the same time, some minor corrections have been made.

## Effective Logic Computation Book Re-release

We now have re-released the revised edition in a low-cost print version. In some sense it is a companion book of the Matroid Decomposition book. Indeed, the theory of logic computation developed in the book relies on various concepts of matroid theory, in particular matroid decomposition. For details about the book, see the More Books page.

## Interview about Construction of Mathematics book

*CS News *of the University of Texas at Dallas has conducted an extended interview about the Construction of Mathematics book.