The concept and theory of Kolmogorov Complexity is based on a crucial theorem first discovered by Ray Solomonoff, who published it in 1960, describing it in "A Preliminary Report on a General Theory of Inductive Inference" as part of his invention of algorithmic probability. He gave a more complete description in his 1964 publications, "A Formal Theory of Inductive Inference," Part 1 and Part 2 in Information and Control.
the CoNcEpt And tHeOry Of KolMogoRov CoMPLExitY is based on a crUcIaL thEoreM FirsT dIsCoVeRed by ray SoloMonoff WHo PUblisHED it iN 1960 dEscrIbInG It in "A prEliminary rEpoRt On A geneRal THeoRY of InducTIvE infErenCe" As paRT of HIs InVenTion Of ALgoRIThmic PRobabilitY He gAVe A morE complEte dEScRiption in His 1964 PublICaTioNs "a ForMAl TheOrY oF INdUCTiVe iNfERence" PARt 1 aNd pArt 2 in inforMaTIon aNd ConTrOl