zeta-ichttp://www.oed.com/dictionary/zeta-ic_adj%3Ftab%3Dmeaning_and_usezeta-ic, adj.
Revised 2018

† zeta-icadjective

Mathematics (Obsolete rare).
  1. 1840–1927
    In or with reference to the work of English mathematician J. J. Sylvester (1814–97): designating multiplication in which the product between two quantities denoted by the same letter but having different subscript indices is a quantity denoted by the same letter which has the sum of these indices as its index; (also) designating a product or function involving such multiplication.
    In essence, zetaic multiplication treats the indices as if they were powers. For example, the product of a1 and a3 is a4, but the product of a1 and b3 is a1b3.
    1. 1840
      Rule for zeta-ic multiplication. Note. An analogous interpretation may be extended to any zeta-ic function whatever.
      J. J. Sylvester in London, Edinburgh, & Dublin Philosophical Magazine vol. 16 37
    2. 1840
      I use the Greek letter ζ to denote that the product of factors to which it is prefixed is to be effected after a certain symbolical manner. This I shall distinguish as the zeta-ic product.
      J. J. Sylvester in London, Edinburgh, & Dublin Philosophical Magazine vol. 16 37
    3. 1927
      We have the determinant of the coefficients equal to the zeta-ic function.
      American Journal of Mathematics vol. 49 519

Originally published as part of the entry for zeta, n.¹

zeta, n.¹ was revised in June 2018.