Fg. Bonales et Rv. Mendoza, EXTENDING THE FORMULA TO CALCULATE THE SPECTRAL-RADIUS OF AN OPERATOR, Proceedings of the American Mathematical Society, 126(1), 1998, pp. 97-103
In a Banach space, Gelfand's formula is used to find the spectral radi
us of a continuous linear operator. In this paper, we show another way
to find the spectral radius of a bounded linear operator in a complet
e topological linear space. We also show that Gelfand's formula holds
in a more general setting if we generalize the definition of the norm
for a bounded linear operator.