### Professor Professor Ron Aharoni

### Distinguished Visitor

Professor Ron Aharoni is an Israeli mathematician, working in finite and infinite combinatorics.

With Nash-Williams and Shelah, he generalized Hall’s marriage theorem. He subsequently proved the appropriate versions of the König theorem and the Menger theorem for infinite graphs.

Professor Aharoni is the author of several nonspecialist books; the most successful is *Arithmetic for Parents*, a book helping parents and elementary school teachers in teaching basic mathematics. He also wrote a book on the connections between *Mathematics, poetry and beauty* and a non-philosophical book on philosophy, *The Cat That is not There*. His last to date book is *Circularity*: *A Common Secret to Paradoxes, Scientific Revolutions and Humor*which binds together mathematics, philosophy and the secrets of humor.

## Events

### Academic Talk

**Using Topology in Combinatorics**

Some of the most resistant problems in combinatorics have succumbed to an unexpected tool – fixed point theorems in algebraic topology. In the talk I will survey some of those.

### Audience

Mathematicians and Researchers

### Date

February 8 (Wednesday) 2017 / 10.30 am – 11.30 am

### Venue

Nanyang Technological University

SPMS MAS Executive Classroom 1 (map)

### Registration Fee

–

### Secondary Math Teachers’ Workshop

**Teaching quadratic equations – a test case for some teaching principles**

Investigation, or direct teaching? This question has been tantalizing teachers over the last few decades. Each method has its advantages and drawbacks. In this workshop I will demonstrate a third, intermediate, way: directed discovery. It is the teacher who leads the class, constructing for them the precise order of the acquisition of concepts, but does so by posing examples to be studied. A main principle in this approach is: no example too simple. In this workshop we shall try to construct a possible order of posing examples to the students, from which they will construct knowledge on quadratic expressions and quadratic equations.

### Audience

Secondary Mathematics Teachers

### Date

February 9 (Thursday) 2017 / 2.30 am – 5.00 pm

### Venue

Academy of Singapore Teachers, Geolab (map)

### Registration Fee

–

### Public Lecture

**Some Principles in the Teaching of Elementary Mathematics**

We shall discuss some basic principles, both of elementary mathematics and of its teaching. There are deep things to know about elementary mathematics, whose knowledge is a prerequisite for good teaching. Some examples of such mathematical principles are the ubiquitous role of the operation of forming a unit and the way from counting to “pure” numbers. Several important teaching principles will also be discussed.

### Audience

General public

### Date

February 10 (Thursday) 2017 / 4.30 am – 5.30 pm

### Venue

National University of Singapore

Block S16, Level 3, LT31 (map)

### Registration Fee

–

### Registration

Please click on the following links to register your attendance.

· Secondary Math Teachers’ Workshop:

MOE teachers register here, non-MOE teachers please register via email