共查询到20条相似文献,搜索用时 15 毫秒
1.
We prove that if an action of a C-semigroup S on a Polish space is syndetic transitive, then the system is either minimal and equicontinuous, or sensitive. Additionally,
we show that if an action of an abelian monoid S on a Polish space has a transitive point x and a periodic orbit O such that [`(Hx)]\overline{Hx} is perfect where H={s∈S:s|
O
is an identity map}, then the system is chaotic. 相似文献
2.
Let k be a field finitely generated over ℚ and p a prime. The torsion conjecture (resp. p-primary torsion conjecture) for abelian varieties over k predicts that the k-rational torsion (resp. the p-primary k-rational torsion) of a d-dimensional abelian variety A over k should be bounded only in terms of k and d. These conjectures are only known for d=1. The p-primary case was proved by Y. Manin, in 1969; the general case was completed by L. Merel, in 1996, after a series of contributions
by B. Mazur, S. Kamienny and others. Due to the fact that moduli of elliptic curves are 1-dimensional, the d=1 case of the torsion conjecture (resp. p-primary torsion conjecture) is closely related to the following. For any k-curve S and elliptic scheme E→S, the k-rational torsion (resp. the p-primary k-rational torsion) is uniformly bounded in the fibres E
s
, s∈S(k). In this paper, we extend this result in the p-primary case to arbitrary abelian schemes over curves. 相似文献
3.
P.V.DANCHEV 《数学学报(英文版)》2004,20(5):893-898
Let G be an abelian p-group and K be a field of the first kind with respect to p of char K ≠p and of sp(K) = N or NU {0}. Then it is shown that the normed Sylow p-subgroup S(KG) is torsion complete if and only if G is bounded (Theorem 1). An analogous fact is proved for the case when K is of the second kind (Theorem 2). These completely settle a conjecture posed by us in Compt. Rend. Acad. Bulg. Sci. (1993) and are also a supplement to our result in the modular case published in Acta Math. Hungar. (1997). 相似文献
4.
Recall that the semigroups S and R are said to be strongly Morita equivalent if there exists a unitary Morita context (S, R.,
S
P
R,R
Q
S
,〈〉
, ⌈⌉) with 〈〉 and ⌈⌉ surjective. For a factorisable semigroup S, we denote ζ
S
= {(s
1, s
2) ∈S×S|ss
1 = ss
2, ∀s∈S}, S' = S/ζ
S
and US-FAct = {
S
M∈S− Act |SM = M and SHom
S
(S, M) ≅M}. We show that, for factorisable semigroups S and M, the categories US-FAct and UR-FAct are equivalent if and only if the semigroups S' and R' are strongly Morita equivalent. Some conditions for a factorisable semigroups to be strongly Morita equivalent to a sandwich
semigroup, local units semigroup, monoid and group separately are also given. Moreover, we show that a semigroup S is completely simple if and only if S is strongly Morita equivalent to a group and for any index set I, S⊗SHom
S
(S, ∐
i∈I
S) →∐
i∈I
S, s⊗t·ƒ↦ (st)ƒ is an S-isomorphism.
The research is partially supported by a UGC(HK) grant #2160092.
Project is supported by the National Natural Science Foundation of China 相似文献
5.
Let S be an abelian *–semigroup in ℚk. We give a sufficient condition for every positive definite function on S to have a unique representing measure on the dual semigroup of S (i.e. S is perfect). To characterize perfectness for any abelian *–semigroupis a challenging, but not yet generally solved problem. In this paper, we characterize the structure of involutions on an abelian *–semigroup which is a subset of ℚk, and show that any conelike *–semigroups in ℚk are perfect. 相似文献
6.
Let S be a grading monoid with quotient group q(S) , let F(S) be the set of fractional ideals of S . For A ∈ F(S) , define A
w
= {x ∈ q(S) \mid J+x \subseteq A for some f.g. ideal J of S with J
-1
=S} and A_ \overline w ={x ∈ q(S)\mid J+x \subseteq A for some ideal J of S with J
-1
=S} . Then w and \overline w are star-operations on F(S) such that w ≤ \overline w . Using these star-operations, we give characterizations of Krull semigroups and pre-Krull semigroups. Also we show that
for every maximal * -ideal P of S , if S
P
is a valuation semigroup, then * -cancellation ideals are * -locally principal ideals, where * is a star-operation on S of finite character. Finally, we show that S is a pre-Krull semigroup (H-semigroup) if and only if the polynomial semigroup S[x] is a pre-Krull semigroup (H-semigroup).
October 15, 1999 相似文献
7.
Donald B. McAlister 《代数通讯》2013,41(6):2002-2023
8.
A class of regular semigroups with regular *- transversals 总被引:6,自引:0,他引:6
Yonghua Li 《Semigroup Forum》2002,65(1):43-57
Let S be a regular semigroup. If there is a subsemigroup S
*
of S and a unary operation * in S satisfying: (1) x
*
∈ S
*
\cap V_ S
*
(x) for all x∈ S; (2) (x
*
)
*
=x for all x∈ S
*
; (3) (x
*
y)
*
=y
*
x
**
and (xy
*
)
*
=y
**
x
*
for all x,y∈ S, then S
*
is called a regular *- transversal of S ; if (3) is replaced with (xy)
*
=y
*
x
*
for all x,y∈ S, then S
*
is called a strongly regular *- transversal of S. In this paper we consider the class of regular semigroups with a strongly regular *- transversal. It is proved that these semigroups are P - regular semigroups. We characterize the structure of the regular semigroups with a strongly regular *- transversal. 相似文献
9.
Joso Vukman 《Acta Mathematica Hungarica》2006,112(3):181-186
Summary Let X be a complex Hilbert space, let L(X) be the algebra of all bounded linear operators on X, and let A(X) ⊂ L(X) be a standard operator algebra, which is closed under the adjoint operation. Suppose there exists a linear mapping D: A(X) → L(X) satisfying the relation D(AA*A) = D(A) A*A + AD(A*)A + AA*D(A), for all A ∈ A(X). In this case D is of the form D(A) = AB-BA, for all A∈ A(X) and some B ∈ L(X), which means that D is a derivation. We apply this result to semisimple H*-algebras. 相似文献
10.
Chris Preston 《Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences)》2009,44(1):63-71
The following is a fundamental construction in the theory of point processes: For a measurable space (X, ɛ) let X
◃ denote the set of all measures on (X, ɛ) taking only values in the set ℕ (and so each p ∈ X
◃ is a finite measure, since p(X) ∈ ℕ); put ɛ
◃ = σ(ɛ
◊), where ɛ
◊ is the set of all subsets of X
◃ having the form {p ∈ X
◃: p(E) = k} with E ∈ ɛ and k ∈ ℕ.
Dedicated to the 80th birthday of Klaus Krickeberg 相似文献
11.
Marin Gutan 《Semigroup Forum》1996,53(1):173-183
Let σ be a nontrivial permutation of ordern. A semigroupS is said to be σ-permutable ifx
1
x
2
...x
n
=x
σ(1)
x
σ(2)
...x
σ(n)
, for every (x
1
,x
2,...,x
n
)∈S
n
. A semigroupS is called(r,t)-commutative, wherer,t are in ℕ*, ifx
1
...x
r
x
r+1
...x
r+t
=x
r+1
...x
r+t
x
1
...x
r
, for every (x
1
,x
2,...,x
r+t
∈S
r+t
. According to a result of M. Putcha and A. Yaqub ([11]), if σ is a fixed-point-free permutation andS is a σ-permutable semigroup then there existsk ∈ ℕ* such thatS is (1,k)-commutative. In [8], S. Lajos raises up the problem to determine the leastk=k(n) ∈ ℕ* such that, for every fixed-point-free permutation σ of ordern, every σ-permutable semigroup is also (1,k)-commutative. In this paper this problem is solved for anyn less than or equal to eight and also whenn is any odd integer. For doing this we establish that if a semigroup satisfies a permutation identity of ordern then inevitably it also satisfies some permutation identities of ordern+1. 相似文献
12.
E. A. Kireeva 《Journal of Mathematical Sciences》2008,152(4):540-557
Let F be a field of prime characteristic p and let V
p be the variety of associative algebras over F without unity defined by the identities [[x, y], z] = 0 and x
4 = 0 if p = 2 and by the identities [[x, y], z] = 0 and x
p = 0 if p > 2 (here [x, y] = xy − yx). Let A/V
p be the free algebra of countable rank of the variety V
p and let S be the T-space in A/V
p generated by x
12
x
22 ⋯ x
k2 + V
2, where k ∈ ℕ if p = 2, and by {ie4170-01}, where k ∈ ℕ and α
1, …, α
2k
∈ {0, p − 1} if p > 2. As is known, S is not finitely generated as a T-space. In the present paper, we prove that S is a limit T-space, i.e., a maximal nonfinitely generated T-space. As a corollary, we have constructed a limit T-space in
the free associative F-algebra without unity of countable rank.
__________
Translated from Fundamentalnaya i Prikladnaya Matematika, Vol. 13, No. 1, pp. 135–159, 2007. 相似文献
13.
Alfred Geroldinger David J. Grynkiewicz Wolfgang A. Schmid 《Acta Mathematica Hungarica》2011,131(4):323-345
For a finite abelian group G and a positive integer d, let s
dℕ(G) denote the smallest integer ℓ∈ℕ0 such that every sequence S over G of length |S|≧ℓ has a nonempty zero-sum subsequence T of length |T|≡0 mod d. We determine s
dℕ(G) for all d≧1 when G has rank at most two and, under mild conditions on d, also obtain precise values in the case of p-groups. In the same spirit, we obtain new upper bounds for the Erdős–Ginzburg–Ziv constant provided that, for the p-subgroups G
p
of G, the Davenport constant D(G
p
) is bounded above by 2exp (G
p
)−1. This generalizes former results for groups of rank two. 相似文献
14.
Invariant tori in nonlinear oscillations 总被引:2,自引:0,他引:2
The boundedness of all the solutions for semilinear Duffing equationx″ + ω2
x + φ(x) =p(t), ω ∈ ℝ+ℕ is proved, wherep (t) is a smooth 2π-periodic function and the perturbation ⌽(x) is bounded. 相似文献
15.
Bernardo?N.?B.?de?Lima 《Bulletin of the Brazilian Mathematical Society》2008,39(2):183-189
Consider an independent site percolation model on ℤ2, with parameter p, equipped with all horizontal and vertical connections. In this note it is shown that given for any parameter p ∈ (0, 1), there exists an integer N such that any binary sequence (word) ξ ∈ {0, 1}ℕ is seen, almost surely, even if all connections whose length is bigger than N are suppressed.
*Partially supported by CNPq. 相似文献
16.
Let S⋃{f} be a set of symmetric polynomials in noncommuting variables. If f satisfies a polynomial identity Σ
i
h
i
*
fh
i
= 1 + Σ
i
g
i
*
s
i
g
i
for some s
i
∈ S ⋃ {1}, then f is obviously nowhere negative semidefinite on the class of tuples of nonzero operators defined by the system of inequalities
s ≥ 0 (s ∈ S). We prove the converse under the additional assumption that the quadratic module generated by S is Archimedean.
Supported by the European network RAAG (EC contract HPRN-CT-2001-00271).
Igor Klep was supported from the state budget by the Slovenian Research Agency (project No. Z1-9570-0101-06). 相似文献
17.
V. N. Konovalov 《Ukrainian Mathematical Journal》2005,57(12):1911-1936
Let s ∈ ℕ and let Δ
+
s
be the set of functions x: I ↦ ℝ on a finite interval I such that the divided differences [x; t
0, ..., t
s
] of order s of these functions are nonnegative for all collections of s + 1 different points t
0, ..., t
s
∈ I. For the classes Δ
+
s
B
p
: = Δ
+
s
∩ B
p
, where B
p
is the unit ball in L
p
, we determine the orders of Kolmogorov and linear widths in the spaces Lq
for 1 ≤ q > p ≤ ∞.
__________
Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 57, No. 12, pp. 1633–1652, December, 2005. 相似文献
18.
We give the L
p
-boundedness for a class of Marcinkiewicz integral operators μΩ, μast;
Ω, λ and μΩ,
s
related to the Littlewood-Paley g-function, g
*
λ-function and the area integral S, respectively. These operators have the kernel functions Ω∈H
1 (S
n−1), the Hardy space on S
n−1. These results in this paper substantially improve and extend the known results.
Received August 25, 1998, Accepted July 6, 1999 相似文献
19.
20.
Martin Kružík 《Applications of Mathematics》2007,52(6):529-543
We study convergence properties of {υ(∇u
k
)}k∈ℕ if υ ∈ C(ℝ
m×m
), |υ(s)| ⩽ C(1+|s|
p
), 1 < p < + ∞, has a finite quasiconvex envelope, u
k
→ u weakly in W
1,p
(Ω; ℝ
m
) and for some g ∈ C(Ω) it holds that ∫Ω
g(x)υ(∇u
k
(x))dx → ∫Ω
g(x)Qυ(∇u(x))dx as k → ∞. In particular, we give necessary and sufficient conditions for L
1-weak convergence of {det ∇u
k
}
k∈ℕ to det ∇u if m = n = p.
Dedicated to Jiří V. Outrata on the occasion of his 60th birthday
This work was supported by the grants IAA 1075402 (GA AV ČR) and VZ6840770021 (MŠMT ČR). 相似文献