Talk:Pincherle derivative

"ad"?

This article begins with this definition:

the Pincherle derivative of a linear operator $\scriptstyle {T:\mathbb {K} [x]\longrightarrow \mathbb {K} [x]}$ on the vector space of polynomials in the variable $\scriptstyle x$ over a field $\scriptstyle {\mathbb {K} }$ is another linear operator $\scriptstyle {T':\mathbb {K} [x]\longrightarrow \mathbb {K} [x]}$ defined as

$T'=[T,x]=Tx-xT=-\operatorname {ad} (x)T,\,$

so that

$T'\{p(x)\}=T\{xp(x)\}-xT\{p(x)\}\qquad \forall p(x)\in \mathbb {K} [x].$

It doesn't say what "ad" is. It should. Michael Hardy (talk) 23:51, 3 July 2009 (UTC)