Nonclassical convolutions and their uses

2014 ◽  
Vol 17 (4) ◽  
Author(s):  
Ivan Dimovski

AbstractA survey of three types of convolutions, depending on arbitrary linear functionals is made. They are convolutions for right inverse operators of the differentiation operator, the Euler operator and the square of the differentiation operator. Three lines of applications of these convolutions are outlined: characterizing their multipliers, the commutants and direct construction of operational calculi.

2013 ◽  
Vol 19 (5) ◽  
pp. 822-826
Author(s):  
Chunyu LIU ◽  
Yan CHEN ◽  
Jinqun HUANG ◽  
Jianxin PEI ◽  
Hao PANG ◽  
...  

Author(s):  
Noriyuki Hori ◽  
Peter N. Nikiforuk ◽  
Kimio Kanai

1965 ◽  
Vol 72 (7) ◽  
pp. 750
Author(s):  
W. Fulks

2019 ◽  
Vol 85 (6) ◽  
Author(s):  
Gabriel G. Plunk ◽  
Matt Landreman ◽  
Per Helander

The condition of omnigenity is investigated, and applied to the near-axis expansion of Garren & Boozer (Phys. Fluids B, vol. 3 (10), 1991a, pp. 2805–2821). Due in part to the particular analyticity requirements of the near-axis expansion, we find that, excluding quasi-symmetric solutions, only one type of omnigenity, namely quasi-isodynamicity, can be satisfied at first order in the distance from the magnetic axis. Our construction provides a parameterization of the space of such solutions, and the cylindrical reformulation and numerical method of Landreman & Sengupta (J. Plasma Phys., vol. 84 (6), 2018, 905840616); Landreman et al. (J. Plasma Phys., vol. 85 (1), 2019, 905850103), enables their efficient numerical construction.


Axioms ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 107
Author(s):  
Juan Carlos García-Ardila ◽  
Francisco Marcellán

Given a quasi-definite linear functional u in the linear space of polynomials with complex coefficients, let us consider the corresponding sequence of monic orthogonal polynomials (SMOP in short) (Pn)n≥0. For a canonical Christoffel transformation u˜=(x−c)u with SMOP (P˜n)n≥0, we are interested to study the relation between u˜ and u(1)˜, where u(1) is the linear functional for the associated orthogonal polynomials of the first kind (Pn(1))n≥0, and u(1)˜=(x−c)u(1) is its Christoffel transformation. This problem is also studied for canonical Geronimus transformations.


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