The pseudo-spectrum of operator pencils
2019 ◽
Vol 13
(05)
◽
pp. 2050100
Keyword(s):
In this paper, we propose a new definition of the pseudo-spectrum for operator pencils, which is associated with two bounded operators [Formula: see text] and [Formula: see text] defined in a Hilbert space. Unlike other definitions available in the literature, we prove, under specific conditions on [Formula: see text] and [Formula: see text], that the pseudo-spectrum for operator pencils is equal to an [Formula: see text]-neighborhood of the generalized spectrum. Moreover, we demonstrate how to use this concept to redefine the pseudo-spectrum of an unbounded operator. We illustrate its usefulness through a numerical example dealing with the Schrödinger operator.
1985 ◽
Vol 37
(4)
◽
pp. 664-681
◽
Keyword(s):
2014 ◽
Vol 47
(29)
◽
pp. 295204
◽
2020 ◽
Vol 41
(3)
◽
pp. 419-440