Glasnik matematički, Vol. 38 No. 1, 2003.
Original scientific paper
On a generalization of the sine function
Tomasz Szostok
Abstract
A function
s(x,y) = inf { ||x + y|| / ||x|| : }
strictly connected with Birkhoff-James orthogonality is considered. This function may be used in functional equations theory, to provide unconditional equations in place of orthogonal equations in the sense of Birkhoff-James. Moreover, we deal with another generalization of the sine function which, in particular leads to a characterization of inner product spaces.
Keywords
Birkhoff-James orthogonality; functional equation; inner product space
Hrčak ID:
1333
URI
Publication date:
1.6.2003.
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