Some constructions of two-associate class PBIB designs

1987 ◽  
Vol 39 (3) ◽  
pp. 671-679
Author(s):  
Snigdha Banerjee ◽  
Sanpei Kageyama ◽  
Bhagwandas
Keyword(s):  



Author(s):  
Yeansu Kim ◽  
Loren Spice ◽  
Sandeep Varma

Abstract Let ${\text G}$ be a reductive group over a $p$-adic field $F$ of characteristic zero, with $p \gg 0$, and let $G={\text G}(F)$. In [ 15], J.-L. Kim studied an equivalence relation called weak associativity on the set of unrefined minimal $K$-types for ${\text G}$ in the sense of A. Moy and G. Prasad. Following [ 15], we attach to the set $\overline{\mathfrak{s}}$ of good $K$-types in a weak associate class of positive-depth unrefined minimal $K$-types a ${G}$-invariant open and closed subset $\mathfrak{g}_{\overline{\mathfrak{s}}}$ of the Lie algebra $\mathfrak{g} = {\operatorname{Lie}}({\text G})(F)$, and a subset $\tilde{{G}}_{\overline{\mathfrak{s}}}$ of the admissible dual $\tilde{{G}}$ of ${G}$ consisting of those representations containing an unrefined minimal $K$-type that belongs to $\overline{\mathfrak{s}}$. Then $\tilde{{G}}_{\overline{\mathfrak{s}}}$ is the union of finitely many Bernstein components of ${G}$, so that we can consider the Bernstein projector $E_{\overline{\mathfrak{s}}}$ that it determines. We show that $E_{\overline{\mathfrak{s}}}$ vanishes outside the Moy–Prasad ${G}$-domain ${G}_r \subset{G}$, and reformulate a result of Kim as saying that the restriction of $E_{\overline{\mathfrak{s}}}$ to ${G}_r\,$, pushed forward via the logarithm to the Moy–Prasad ${G}$-domain $\mathfrak{g}_r \subset \mathfrak{g}$, agrees on $\mathfrak{g}_r$ with the inverse Fourier transform of the characteristic function of $\mathfrak{g}_{\overline{\mathfrak{s}}}$. This is a variant of one of the descriptions given by R. Bezrukavnikov, D. Kazhdan, and Y. Varshavsky in [8] for the depth-$r$ Bernstein projector.





2019 ◽  
Vol 19 (08) ◽  
pp. 2050155
Author(s):  
Gaohua Tang ◽  
Guangke Lin ◽  
Yansheng Wu

In this paper, we introduce the concept of the associate class graph of zero-divisors of a commutative ring [Formula: see text], denoted by [Formula: see text]. Some properties of [Formula: see text], including the diameter, the connectivity and the girth are investigated. Utilizing this graph, we present a new class of counterexamples of Beck’s conjecture on the chromatic number of the zero-divisor graph of a commutative ring.





1957 ◽  
Vol 28 (2) ◽  
pp. 349-361 ◽  
Author(s):  
Clyde Young Kramer ◽  
Ralph Allan Bradley


1981 ◽  
Vol 30 (1-2) ◽  
pp. 57-64
Author(s):  
Sunanda Mukhopadhyay

For the problem of estimation of all elementary treatment contraata, restrictina ourselves to PBIBD's with two clus association schemea under a mixed model we follow the approach of Sinha and Sinha (1969) to study the behaviour of tho average variance [Formula: see text] as a function of [Formula: see text] and also as a function of the auociation scheme to some extent. The functional form of [Formula: see text] turna out to be the Jame as that under fixed effects model and either [Formula: see text] for all admissible θ>0. We got that when a BIB dosian does not exist with tho alven parameters a GO design with [Formula: see text] if it exists, is A-optimal within the class of all PBIB designs with two associate class association schemes. This proves that in respect of A-optimality, the result of Chong (1978) can be extended to all GD designs with [Formula: see text] if we restrict ourselves to such PBIB dosigns.





Author(s):  
D. A. Preece ◽  
Willard H. Clatworthy


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