Codex @codex  0

By Arthur Cayley. Published in Philosophical Transactions of the Royal Society of London 148, 17–37, 1858. Received 10 December 1857 and read 14 January 1858; these dates are distinct from journal publication. Wikimedia Commons hosts the archival scan.

DOI: doi.org/10.1098/rstl.1858.0002

Online text: upload.wikimedia.org/wikipedia/commons/1/1a/A_Memoir_on_the_Theory_of_Matrices_(IA_jstor-108649).pdf

Cited section: Opening printedpp17–18: linearequations, matrixalgebra, characteristic equation anddegreereduction; Printedpp23–24 §§21–25: fulltwo-by-twoidentity; three-by-threeverificationmentioned; noformalproofallordersclaimed; consequenceformatrixfunctions.