In this article, we give the properties of mappings associated with the upper semi-inner product , lower semi-inner product and Lumer semi-inner product which generate the norm on a real normed space. Furthermore, we establish applications to the Birkhoff orthogonality and characterization of best approximants.
Quadratic: Journal of Innovation and Technology in Mathematics and Mathematics Education encompasses original research in mathematics and mathematics education and not submitted to another journal or conference from a range of research fields such as research and development, experimental research, ...