x.
One mathematician with this last name developed an algebra in which the most general associativity relations are x and y x times y equals y times x and quantity x-squared times y, close quantity times x equals x-squared times quantity y times x. Another mathematician with this last name proved the theorem that a simple, closed curve divides the plain disjoint interior and exterior regions; such curves also bear his name. Still another mathematician with this last is the second namesake of a method in which a matrix is inverted by reducing it reduced row-echelon form. For 10 points, give this last name of mathematician Wilhelm, who names a form of matrix elimination with Carl Friedrich Gauss.
One mathematician with this last name developed an algebra in which the most general associativity relations are x and y x
{Jordan}