文摘
A famous result of Lieb establishes that the map class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0024379516304852&_mathId=si1.gif&_user=111111111&_pii=S0024379516304852&_rdoc=1&_issn=00243795&md5=61f1c5983da1fab08dab2cead45e20d6" title="Click to view the MathML source">(A,B)↦tr[K⁎A1−tKBt]class="mathContainer hidden">class="mathCode"> is jointly concave in the pair class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0024379516304852&_mathId=si2.gif&_user=111111111&_pii=S0024379516304852&_rdoc=1&_issn=00243795&md5=df2d24d86109571d1b398987eb3a6e15" title="Click to view the MathML source">(A,B)class="mathContainer hidden">class="mathCode"> of positive definite matrices, where K is a fixed matrix and class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0024379516304852&_mathId=si15.gif&_user=111111111&_pii=S0024379516304852&_rdoc=1&_issn=00243795&md5=f37be1da849e238387b2139ccadce957" title="Click to view the MathML source">t∈[0,1]class="mathContainer hidden">class="mathCode">. In this paper we show that Lieb's function admits an explicit semidefinite programming formulation for any rational class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0024379516304852&_mathId=si15.gif&_user=111111111&_pii=S0024379516304852&_rdoc=1&_issn=00243795&md5=f37be1da849e238387b2139ccadce957" title="Click to view the MathML source">t∈[0,1]class="mathContainer hidden">class="mathCode">. Our construction makes use of a semidefinite formulation of weighted matrix geometric means. We provide an implementation of our constructions in Matlab.