Statistical convergence

In the first chapter of this thesis that consists of three chapters, we give some fundamental definitions, theorems which will be used in the later chapters and lacunary statistical convergence concept. In the second chapter we give some properties of the difference sequence spaces (?) (?) (?) ? 0 l , c and c , and we also give the generalised difference sequence spaces (?m ) (?m ) (?m ) ? 0 l , c and c , m? ?? . In the third chapter which is the last and the original part of the thesis, we define the sequence spaces S(? , ?) and S? (? , ?), and give some inclusion relations between these spaces. Key Words: natural density, statistical convergence, statistical Cauchy sequence, strongly Cesàro convergence, strongly p-Cesàro convergence, lacunary statistical convergence, difference sequence spaces, generalised difference sequence spaces.