C19: from Greek nabla stringed instrument, because it is shaped like a harp
del in British English
(dɛl)
noun
mathematics
the differential operator i(∂/∂x) + j(∂/∂y) + k(∂/∂z), where i, j, and k are unit vectors in the x, y, and z directions
Symbol: ∇. Also called: nabla
Examples of 'nabla' in a sentence
nabla
The first type relates nabla and delta type fractional sums and differences.
Thabet Abdeljawad 2013, 'On Delta and Nabla Caputo Fractional Differences and Dual Identities', Discrete Dynamics in Nature and Societyhttp://dx.doi.org/10.1155/2013/406910. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)
We show that two recent definitions of discrete nabla fractional sum operators are related.
Thabet Abdeljawad, Ferhan M. Atici 2012, 'On the Definitions of Nabla Fractional Operators', Abstract and Applied Analysishttp://dx.doi.org/10.1155/2012/406757. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)