# 10 Turkish lira note & bill

## 10 Turkish lira Front

10 Turkish lira the front is President Mustafa Kemal Atatürk

Holographic Stripe

The foil is made up of various motifs that are in harmony with the note design. When looking at a banknote from various angles, these motifs display colourful and shiny reflections. "TL" letters in the rectangle change into the denomination numeral.

Security Thread

Embedded in the paper, the thread bears the letters "TL" and the denomination numeral "10". When holding a banknote to the light, the thread can be seen from both sides as a continuous line.

Latent Number

Concealed "10" can be seen when the banknote is tilted horizontally at the eye level.

Watermark

Reproduces the small version of the Atatürk's portrait located on the obverse side of the banknote and the denomination numeral "10". It can be seen from both sides when held up to the light.

Intaglio Printing

Located at various positions on the obverse side of the banknotes and can be felt with fingertips.

Iridescent Stripe

Gives different colour effects, shifting into a golden yellow. The denomination numeral "10" and the letters "TL" can be seen when the banknote is tilted.

## 10 Turkish lira Back

10 Turkish lira the back is Prof Dr. Cahit Arf

Cahit Arf (Turkish: [dʒahit aɾf]; 11 October 1910 – 26 December 1997) was a Turkish mathematician. He is known for the Arf invariant of a quadratic form in characteristic 2 (applied in knot theory and surgery theory) in topology, the Hasse–Arf theorem in ramification theory, Arf semigroups, and Arf rings.

Arf's influence on science in general and mathematics in particular was profound. Although he had very few formal students, many of the mathematicians of Turkey, at some time of their careers, had fruitful discussions on their field of interest with him and had received support and encouragement.

He facilitated the now-celebrated visit of Robert Langlands to Turkey (now famous for the Langlands program, among many other things); during which Langlands worked out some arduous calculations on the epsilon factors of Artin L-functions.

Arf's portrait is depicted on the reverse of the Turkish 10 lira banknote issued in 2009.

Middle East Technical University Department of Mathematics organizes a special lecture session called the Cahit Arf lecture each year in memory of Arf.