Kronecker delta

Noun

Kronecker delta (plural Kronecker deltas)

1. A binary function, written as δ with two subscripts, which evaluates to 1 when its arguments are equal, and 0 otherwise.
   • The Kronecker delta #92;delta#95;#123;ij#125; is an example of an isotropic tensor. That is, its components remain invariant with rotation of coordinate axes.1998, Robert G. Deissler, Turbulent Fluid Motion, Taylor & Francis, page 24
   • The permutation symbol and the Kronecker delta prove to be very useful in proving vector identities.2007, J. N. Reddy, An Introduction to Continuum Mechanics, Cambridge University Press, page 20, Further, the Kronecker delta and the permutation symbol are related by the identity, known as the e-δ...

   Synonyms:

   Kronecker tensor, substitution tensor

2. A unary function, written as δ with a single index, which evaluates to 1 at zero, and 0 elsewhere.