Let
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303742&_mathId=si1.gif&_user=111111111&_pii=S0022247X16303742&_rdoc=1&_issn=0022247X&md5=2642dd6c0a1142a947d44e9d01c2d3b9" title="Click to view the MathML source">Hclass="mathContainer hidden">class="mathCode"> be a Hilbert space,
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303742&_mathId=si139.gif&_user=111111111&_pii=S0022247X16303742&_rdoc=1&_issn=0022247X&md5=9eef978474e7c1ad8117c2518b8311b9" title="Click to view the MathML source">L(H)class="mathContainer hidden">class="mathCode"> the algebra of bounded linear operators on
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303742&_mathId=si1.gif&_user=111111111&_pii=S0022247X16303742&_rdoc=1&_issn=0022247X&md5=2642dd6c0a1142a947d44e9d01c2d3b9" title="Click to view the MathML source">Hclass="mathContainer hidden">class="mathCode"> and
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303742&_mathId=si3.gif&_user=111111111&_pii=S0022247X16303742&_rdoc=1&_issn=0022247X&md5=d17fda4ed8ac8094608d1f2b46e0327d" title="Click to view the MathML source">W∈L(H)class="mathContainer hidden">class="mathCode"> a positive operator such that
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303742&_mathId=si4.gif&_user=111111111&_pii=S0022247X16303742&_rdoc=1&_issn=0022247X&md5=7b44df5c427e5b10d04111fcb66e2b8a" title="Click to view the MathML source">W1/2class="mathContainer hidden">class="mathCode"> is in
the p-Schatten
class, for some
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303742&_mathId=si158.gif&_user=111111111&_pii=S0022247X16303742&_rdoc=1&_issn=0022247X&md5=43e7ecdb29927a185e2121440427cfab" title="Click to view the MathML source">1≤p<∞class="mathContainer hidden">class="mathCode">. Given
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303742&_mathId=si6.gif&_user=111111111&_pii=S0022247X16303742&_rdoc=1&_issn=0022247X&md5=2fa9d05490322ea9bce5c62697165f30" title="Click to view the MathML source">A∈L(H)class="mathContainer hidden">class="mathCode"> with closed range and
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303742&_mathId=si100.gif&_user=111111111&_pii=S0022247X16303742&_rdoc=1&_issn=0022247X&md5=039deedf4f9e53dd24a664e9fd65a97a" title="Click to view the MathML source">B∈L(H)class="mathContainer hidden">class="mathCode">, we study
the following weighted approximation problem: analyze
the existence of
class="formula" id="fm0010">
where
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303742&_mathId=si9.gif&_user=111111111&_pii=S0022247X16303742&_rdoc=1&_issn=0022247X&md5=7c243f37d1a7a4b5f0fc75b0ecb2a078" title="Click to view the MathML source">‖X‖p,W=‖W1/2X‖pclass="mathContainer hidden">class="mathCode">. In this paper we prove that
the existence of this minimum is equivalent to a compatibility condition between
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303742&_mathId=si10.gif&_user=111111111&_pii=S0022247X16303742&_rdoc=1&_issn=0022247X&md5=ffaf32fc4ac5e32349d77858cf2d538b" title="Click to view the MathML source">R(B)class="mathContainer hidden">class="mathCode"> and
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303742&_mathId=si11.gif&_user=111111111&_pii=S0022247X16303742&_rdoc=1&_issn=0022247X&md5=81c22a282eaff9513080ec093b91c49a" title="Click to view the MathML source">R(A)class="mathContainer hidden">class="mathCode"> involving
the weight
W, and we characterize
the operators which minimize this problem as
W-inverses of
A in
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303742&_mathId=si10.gif&_user=111111111&_pii=S0022247X16303742&_rdoc=1&_issn=0022247X&md5=ffaf32fc4ac5e32349d77858cf2d538b" title="Click to view the MathML source">R(B)class="mathContainer hidden">class="mathCode">.