On Bounded Linear Operations in b-Hilbert Spaces and their Numerical Ranges

In this paper, we introduce the notions of b-bounded linear operator, b-numericalrange and b-numerical radius in a b-Hilbert space and describe some of their properties. Thenwe will show that this new numerical range (radius) can be considered as a usual numericalrange (radius) in a Hilbert space, so it shares many useful properties with numerical range(radius)