∂

The

such as ${\displaystyle {\partial z}/{\partial x}}$ (read as "the partial derivative of z with respect to x").

The symbol was originally introduced in 1770 by Nicolas de Condorcet, who used it for a partial differential, and adopted for the partial derivative by Adrien-Marie Legendre in 1786.^[3] It represents a specialized cursive type of the letter d, just as the

Names and coding

The symbol is variously referred to as "partial", "curly d", "funky d", "rounded d", "curved d", "dabba", "number 6 mirrored",^[6] or "Jacobi's delta",^[5] or as "del"^[7] (but this name is also used for the "nabla" symbol ∇). It may also be pronounced simply "dee",^[8] "partial dee",^[9][10] "doh",^[11][12] or "die".^[13]

The Unicode character U+2202 ∂ PARTIAL DIFFERENTIAL is accessed by

glyph: ${\displaystyle \partial }$) is accessed by \partial.

Uses

∂ is also used to denote the following:

• The Jacobian ${\displaystyle {\frac {\partial (x,y,z)}{\partial (u,v,w)}}}$.
• The boundary of a set in topology.
• The boundary operator on a chain complex in homological algebra.
• The boundary operator of a differential graded algebra.
• The conjugate of the
  Dolbeault operator on complex differential forms
  .
• The boundary ∂(S) of a set of vertices S in a graph is the set of edges leaving S, which defines a cut.

See also

• d'Alembert operator
• Differentiable programming
• Differential operator § Notations
• List of mathematical symbols
• Notation for differentiation
• 𝒹
  (Unicode MATHEMATICAL SCRIPT SMALL D)
• ꝺ (lowercase d in Insular script)
• δ
  (lowercase Greek Delta)
• д
  (lowercase Cyrillic De, looks similar when italicized in some typefaces)

References

Look up ∂ in Wiktionary, the free dictionary.