Hi everybody,

I am going to present the country that I chose which is Ireland and one of its famous mathematician.

Some facts about the country:

-an Island to the North-West of Continental Europe.

-3rd Largest in Europe and 20th on Earth

-Politically divided between the Republic of Ireland (also called Eire) and Northern Ireland (also called Ulster) which is part of the UK.

-Population : Around 6.4 millions of people (4.6 in the republic of Ireland and 1.8 in Northern Ireland.

-Irish culture has a significant influence on other cultures in particular in literature and a little in science.

-Strong indigenous culture expressed through Gaelic games (football, hurling and handball), Irish music and language.

-The Irish favorite Beer is called Guiness.

Sir William Rowan Hamilton

He was born on the 4th August 1805 and he died on the 2nd September 1865.

žHe was an Irish physicist, astronomer, and mathematician, who made important contributions to classical mechanics, optics, and algebra. 
      He studied mechanical and optical systems which  led him to discover new mathematical concepts and techniques. 

      His greatest contribution is the reformulation of Newtonian mechanics, now called Hamiltonian mechanics. In mathematics, he is perhaps best known as the inventor of quaternions.

                 The Quaternions :

           They were first described in 1843 by Hamilton and applied to mechanics in three-dimensional space. 

           In mathematics, the quaternions are a 4-dimensional number system where a quantity representing a 3-dimensional rotation can be described by just an angle and a vector.

           Hamilton defined a quaternion as the quotient of two directed lines in a 3D space or equivalently as the quotient of two vectors.

      Quaternions can also be represented as the sum of a scalar and a vector.

      A feature of quaternions is that the product of two quaternions is noncommutative.(ex: a x b does not always equal b x a) 

    Quaternions are used in both theoretical and applied mathematics, in particular for calculations involving three-dimensional rotations such as in 3D computer graphics and computer vision. 
   Today, the quaternions are also used in signal processing, and orbital mechanics, mainly for representing rotations/orientations.