scholarly journals Cameron–Liebler k-sets in subspaces and non-existence conditions

Author(s):  
Jan De Beule ◽  
Jonathan Mannaert ◽  
Leo Storme
Keyword(s):  
Networks ◽  
1994 ◽  
Vol 24 (7) ◽  
pp. 385-394 ◽  
Author(s):  
Yeroon van den Berg ◽  
David M. Panton

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Qiang Li ◽  
Yongxiang Li

The existence results of positiveω-periodic solutions are obtained for the second-order functional differential equation with multiple delaysu″(t)+a(t)u(t)=f(t,u(t),u(t−τ1(t)),…,u(t−τn(t))), wherea(t)∈C(ℝ)is a positiveω-periodic function,f:ℝ×[0,+∞)n+1→[0,+∞)is a continuous function which isω-periodic int, andτ1(t),…,τn(t)∈C(ℝ,[0,+∞))areω-periodic functions. The existence conditions concern the first eigenvalue of the associated linear periodic boundary problem. Our discussion is based on the fixed-point index theory in cones.


2004 ◽  
Vol 2004 (10) ◽  
pp. 487-534 ◽  
Author(s):  
M. B. Sheftel

We study point and higher symmetries of systems of the hydrodynamic type with and without an explicit dependence ont,x. We consider such systems which satisfy the existence conditions for an infinite-dimensional group of hydrodynamic symmetries which implies linearizing transformations for these systems. Under additional restrictions on the systems, we obtain recursion operators for symmetries and use them to construct infinite discrete sets of exact solutions of the studied equations. We find the interrelation between higher symmetries and recursion operators. Two-component systems are studied in more detail thann-component systems. As a special case, we consider Hamiltonian and semi-Hamiltonian systems of Tsarëv.


2017 ◽  
Vol 22 (6) ◽  
pp. 1510-1534
Author(s):  
Ryan S. Mattson ◽  
Philippe de Peretti

In this paper, we use the weak separability criterion to check for the existence of six different monetary aggregates reported by the Center of Financial Stability (CFS). We implement an extended version of the semi-nonparametric tests introduced by Barnett and de Peretti on US monthly data from January 1967 to December 2012. The test, first, checks for the necessary existence conditions of an overall utility function and a monetary subutility function, and then tests for the separability of the latter. On different subsamples, our results suggest that only the DM1 aggregate meets the separability criterion. Implemented on macroeconomic data, we have tested a joint assumption about separability and the existence of a representative agent. Thus, the rejection of the null could also be due to the rejection of stringent Gorman's conditions. More advanced tests for weak separability are clearly required to confirm the results found in this paper.


2014 ◽  
Vol 51 (1) ◽  
pp. 111-123
Author(s):  
THADDEUS METZ

AbstractTaking the good (generosity), the true (enquiry), and the beautiful (creativity) as exemplars of what can make a life noticeably meaningful, elsewhere I have advanced a principle that entails and plausibly explains all three. Specifically, I have proffered the view that great meaning in life, at least in so far as it comes from this triad, is a matter of positively orienting one's rational nature towards fundamental conditions of human existence, conditions of human life responsible for much else about it. Iddo Landau has raised important objections to this principle, arguing in particular that contouring one's rationality towards fundamentality is neither necessary nor sufficient for great meaning in life. In this article, I reply to Landau's objections to the fundamentality account of what makes life very meaningful. I thereby aim to enrich reflection about what it is about the lives of Nelson Mandela, Mother Teresa, Albert Einstein, and Pablo Picasso that made them so significant as well as to indicate how fundamentality implicitly plays a key role in theistic conceptions of meaning in life.


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