Write the following list of characters into a correctly formed sentence: IfKempe'sworkonthefourcolourtheoremisnotmentionedinhisobituarythenitisreasonabletoask:whatwasconsideredhismostimportantcontributiontomathematicsin1923?TheansweristhatMacMahon,whocontributestothedescriptionofKempe'smathematicalachievements,consideredhisMemoironthetheoryofmathematicalformpublishedinthePhilosophicalTransactionsofTheRoyalSocietyin1886tobehismostimportantwork.
If Kempe's work on the four colour theorem is not mentioned in his obituary then it is reasonable to ask: what was considered his most important contribution to mathematics in 1923? The answer is that MacMahon , who contributes to the description of Kempe's mathematical achievements, considered his Memoir on the theory of mathematical form published in the Philosophical Transactions of The Royal Society in 1886 to be his most important work.