翻訳と辞書
Words near each other
・ Pinchem, Clark County, Kentucky
・ Pinchem, Kentucky
・ Pinchem, Todd County, Kentucky
・ Pincheon Green
・ Pincher
・ Pincher Creek
・ Pincher Creek (provincial electoral district)
・ Pincher Creek Airport
・ Pincher Creek Echo
・ Pincher Creek Panthers
・ Pincher Creek-Crowsnest
・ Pincher Creek-Macleod
・ Pincher Martin
・ Pincher Station
・ Pincherle
Pincherle derivative
・ Pincherle polynomials
・ Pinchers
・ Pinchface
・ Pinchgut Creek
・ Pinchgut Opera
・ Pinchi Lake
・ Pinchie, British Columbia
・ Pinchimuru
・ Pinchin Johnson & Associates
・ Pinchinthorpe
・ Pinchinthorpe railway station
・ Pinchitos
・ Pincho
・ Pincho Man


Dictionary Lists
翻訳と辞書 辞書検索 [ 開発暫定版 ]
スポンサード リンク

Pincherle derivative : ウィキペディア英語版
Pincherle derivative

In mathematics, the Pincherle derivative ''T’'' of a linear operator ''T'':K() → K() on the vector space of polynomials in the variable ''x'' over a field K is the commutator of ''T'' with the multiplication by ''x'' in the algebra of endomorphisms End(K()). That is, ''T’'' is another linear operator ''T’'':K() → K()
: T' := () = Tx-xT = -\operatorname(x)T,\,
so that
: T'\=T\-xT\\qquad\forall p(x)\in \mathbb().
This concept is named after the Italian mathematician Salvatore Pincherle (1853–1936).
== Properties ==
The Pincherle derivative, like any commutator, is a derivation, meaning it satisfies the sum and products rules: given two linear operators \scriptstyle S and \scriptstyle T belonging to \scriptstyle \operatorname \left( \mathbb K() \right)
#\scriptstyle ;
#\scriptstyle where \scriptstyle is the composition of operators ;
One also has \scriptstyle where \scriptstyle is the usual Lie bracket, which follows from the Jacobi identity.
The usual derivative, ''D'' = ''d''/''dx'', is an operator on polynomials. By straightforward computation, its Pincherle derivative is
: D'= \left(_ = 1.
This formula generalizes to
: (D^n)'= \left(\right)' = nD^,
by induction. It proves that the Pincherle derivative of a differential operator
: \partial = \sum a_n \over } = \sum a_n D^n
is also a differential operator, so that the Pincherle derivative is a derivation of \scriptstyle \operatorname(\mathbb K ()) .
The shift operator
: S_h(f)(x) = f(x+h) \,
can be written as
: S_h = \sum_ \over }D^n
by the Taylor formula. Its Pincherle derivative is then
: S_h' = \sum_ \over }D^ = h \cdot S_h.
In other words, the shift operators are eigenvectors of the Pincherle derivative, whose spectrum is the whole space of scalars \scriptstyle.
If ''T'' is shift-equivariant, that is, if ''T'' commutes with ''S''''h'' or \scriptstyle, then we also have \scriptstyle, so that \scriptstyle T' is also shift-equivariant and for the same shift \scriptstyle h.
The "discrete-time delta operator"
: (\delta f)(x) = \over h }
is the operator
: \delta = (S_h - 1),
whose Pincherle derivative is the shift operator \scriptstyle.

抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)
ウィキペディアで「Pincherle derivative」の詳細全文を読む



スポンサード リンク
翻訳と辞書 : 翻訳のためのインターネットリソース

Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.