On certain infinitely differentiable function spaces

Author(s):  
Manuel Valdivia
1976 ◽  
Vol 17 (1) ◽  
pp. 53-56 ◽  
Author(s):  
B. Fisher

In a recent paper [1], Jones extended the definition of the convolution of distributions so that further convolutions could be defined. The convolution w1*w2 of two distributions w1 and w2 was defined as the limit ofithe sequence {wln*w2n}, provided the limit w exists in the sense thatfor all fine functions ф in the terminology of Jones [2], wherew1n(x) = wl(x)τ(x/n), W2n(x) = w2(x)τ(x/n)and τ is an infinitely differentiable function satisfying the following conditions:(i) τ(x) = τ(—x),(ii)0 ≤ τ (x) ≤ l,(iii)τ (x) = l for |x| ≤ ½,(iv) τ (x) = 0 for |x| ≥ 1.


Author(s):  
B. Fisher

The product of two distributions f and g on the open interval (a, b), where −∞ ≤ a < b ∞, was defined in (1) as the limit of the sequence {fn·gn} provided this sequence is regular in (a, b), wherefor n = 1, 2, … and ρ is a fixed infinitely differentiable function having the following properties:


2004 ◽  
Vol 2004 (16) ◽  
pp. 833-845 ◽  
Author(s):  
C. K. Li ◽  
V. Zou

Letρ(s)be a fixed infinitely differentiable function defined onR+=[0,∞)having the properties: (i)ρ(s)≥0, (ii)ρ(s)=0fors≥1, and (iii)∫Rmδn(x)dx=1whereδn(x)=cmnmρ(n2r2)andcmis the constant satisfying (iii). We overcome difficulties arising from computing∇lδnand express this regular sequence by two mutual recursions and use a Java swing program to evaluate corresponding coefficients. Hence, we are able to imply the distributional productr−k⋅∇lδfork=1,2,…andl=0,1,2,…with the help of Pizetti's formula and the normalization.


2018 ◽  
Vol 9 (3) ◽  
pp. 334-343 ◽  
Author(s):  
Lei Li ◽  
Dongyang Chen ◽  
Qing Meng ◽  
Ya-Shu Wang

1968 ◽  
Vol 32 ◽  
pp. 323-330
Author(s):  
Yoshio Kato

Let Ω be a domain in the (n + 1)-dimensional euclidian space Rn+1. A linear partial differential operator P with coefficients in C∞(Ω) (resp. in Cω(Ω)) will be termed hypoelliptic (resp. analytic-hypoelliptic) in Ω if a distribution u on Ω (i.e. u ∈ D′(Ω)) is an infinitely differentiable function (resp. an analytic function) in every open set of Ω where Pu is an infinitely differentiable function (resp. an analytic function).


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