sp0020">For semifinite algebras, considering <span id="mmlsi4" class="mathmlsrc"><span class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S000187081600089X&_mathId=si4.gif&_user=111111111&_pii=S000187081600089X&_rdoc=1&_issn=00018708&md5=3722ddfe4567c9a6e25dc5b53e7909c1" title="Click to view the MathML source">L<sup>psup>=L<sup>psup>(M,τ)span><span class="mathContainer hidden"><span class="mathCode">span>span>span> as an interpolation space between <span id="mmlsi2" class="mathmlsrc"><span class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S000187081600089X&_mathId=si2.gif&_user=111111111&_pii=S000187081600089X&_rdoc=1&_issn=00018708&md5=4285a449ccceed0f783fe23fde95a2b2" title="Click to view the MathML source">Mspan><span class="mathContainer hidden"><span class="mathCode">span>span>span> and its predual <span id="mmlsi5" class="mathmlsrc"><span class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S000187081600089X&_mathId=si5.gif&_user=111111111&_pii=S000187081600089X&_rdoc=1&_issn=00018708&md5=7d85ae9623adb58d300234549b106981" title="Click to view the MathML source">M<sub>⁎sub>span><span class="mathContainer hidden"><span class="mathCode">span>span>span> one arrives at a certain self-extension of <span id="mmlsi1" class="mathmlsrc"><span class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S000187081600089X&_mathId=si1.gif&_user=111111111&_pii=S000187081600089X&_rdoc=1&_issn=00018708&md5=437d0cd87cc21f3f3e496072d55e0cca" title="Click to view the MathML source">L<sup>psup>span><span class="mathContainer hidden"><span class="mathCode">span>span>span> that is a kind of noncommutative Kalton–Peck space and carries a natural bimodule structure. Some interesting properties of these spaces are presented.
sp0030">For general algebras, including those of type III, the interpolation mechanism produces two (rather than one) extensions of one sided modules, one of left-modules and the other of right-modules. Whether or not one may find (nontrivial) self-extensions of bimodules in all cases is left open.