Recursos de colección

Project Euclid (Hosted at Cornell University Library) (202.070 recursos)

Tokyo Journal of Mathematic

KODAMA, Shun

3. Harmonic Analysis on the Space of $p$-adic Unitary Hermitian Matrices, Mainly for Dyadic Case

HIRONAKA, Yumiko
We are interested in harmonic analysis on $p$-adic homogeneous spaces based on spherical functions. In the present paper, we investigate the space $X$ of unitary hermitian matrices of size $m$ over a ${\mathfrak p}$-adic field $k$ mainly for dyadic case, and give the unified description with our previous papers for non-dyadic case. The space becomes complicated for dyadic case, and the set of integral elements in $X$ has plural Cartan orbits. We introduce a typical spherical function $\omega(x;z)$ on $X$, study its functional equations, which depend on $m$ and the ramification index $e$ of $2$ in $k$, and give its...

4. Harmonic Analysis on the Space of $p$-adic Unitary Hermitian Matrices, Mainly for Dyadic Case

HIRONAKA, Yumiko
We are interested in harmonic analysis on $p$-adic homogeneous spaces based on spherical functions. In the present paper, we investigate the space $X$ of unitary hermitian matrices of size $m$ over a ${\mathfrak p}$-adic field $k$ mainly for dyadic case, and give the unified description with our previous papers for non-dyadic case. The space becomes complicated for dyadic case, and the set of integral elements in $X$ has plural Cartan orbits. We introduce a typical spherical function $\omega(x;z)$ on $X$, study its functional equations, which depend on $m$ and the ramification index $e$ of $2$ in $k$, and give its...

5. A Function Determined by a Hypersurface of Positive Characteristic

OHTA, Kosuke
Let $R=k\jump{X_1, \dots ,X_{n+1}}$ be a formal power series ring over a perfect field $k$ of characteristic $p>0$, and let $\mathfrak{m} = (X_1 , \dots , X_{n+1})$ be the maximal ideal of $R$. Suppose $0\neq f \in\mathfrak{m}$. In this paper, we introduce a function $\xi_{f}(x)$ associated with a hypersurface $R/(f)$ defined on the closed interval $[0,1]$ in $\mathbb{R}$. The Hilbert-Kunz multiplicity and the F-signature of $R/(f)$ appear as the values of our function $\xi_{f}(x)$ on the interval's endpoints. The F-signature of the pair, denoted by $s(R,f^{t})$, was defined by Blickle, Schwede and Tucker. Our function $\xi_{f}(x)$ is integrable, and the...

6. A Function Determined by a Hypersurface of Positive Characteristic

OHTA, Kosuke
Let $R=k\jump{X_1, \dots ,X_{n+1}}$ be a formal power series ring over a perfect field $k$ of characteristic $p>0$, and let $\mathfrak{m} = (X_1 , \dots , X_{n+1})$ be the maximal ideal of $R$. Suppose $0\neq f \in\mathfrak{m}$. In this paper, we introduce a function $\xi_{f}(x)$ associated with a hypersurface $R/(f)$ defined on the closed interval $[0,1]$ in $\mathbb{R}$. The Hilbert-Kunz multiplicity and the F-signature of $R/(f)$ appear as the values of our function $\xi_{f}(x)$ on the interval's endpoints. The F-signature of the pair, denoted by $s(R,f^{t})$, was defined by Blickle, Schwede and Tucker. Our function $\xi_{f}(x)$ is integrable, and the...

7. Second Sectional Classes of Polarized Three-folds

FUKUMA, Yoshiaki
Let $X$ be a smooth complex projective variety of dimension $3$ and $L$ an ample line bundle on $X$. In this paper we study the second sectional class $\mathrm{cl}_{2}(X,L)$ of $(X,L)$. First we show the inequality $\mathrm{cl}_{2}(X,L)\geq L^{3}-1$, and we characterize $(X,L)$ with $-1\leq \mathrm{cl}_{2}(X,L)-L^{3}\leq 3$. Furthermore the classification of pairs $(X,L)$ with small second sectional classes is obtained. We also classify $(X,L)$ with $2L^{3}\geq \mathrm{cl}_{2}(X,L)$.

8. Second Sectional Classes of Polarized Three-folds

FUKUMA, Yoshiaki
Let $X$ be a smooth complex projective variety of dimension $3$ and $L$ an ample line bundle on $X$. In this paper we study the second sectional class $\mathrm{cl}_{2}(X,L)$ of $(X,L)$. First we show the inequality $\mathrm{cl}_{2}(X,L)\geq L^{3}-1$, and we characterize $(X,L)$ with $-1\leq \mathrm{cl}_{2}(X,L)-L^{3}\leq 3$. Furthermore the classification of pairs $(X,L)$ with small second sectional classes is obtained. We also classify $(X,L)$ with $2L^{3}\geq \mathrm{cl}_{2}(X,L)$.

9. A Lower Bound of the Dimension of the Vector Space Spanned by the Special Values of Certain Functions

HIROSE, Minoru; KAWASHIMA, Makoto; SATO, Nobuo
Let $K$ be a number field. Fix a finite set of analytic functions $\bold{f}_{\infty}:=\{f_{1,\infty}(x),\ldots,f_{s,\infty}(x) \}$ defined on $\{x\in \mathbb{C} \mid |x|>1\}$ (resp. $\mathbb{C}_p$-valued functions $\bold{f}_{p}:=\{f_{1,p}(x),\ldots,f_{s,p}(x) \}$ defined on $\{x\in \mathbb{C}_p \mid |x|_p>1\}$). For $\beta\in K$, we denote the $K$-vector space spanned by $f_{1,\infty}(\beta),\ldots,f_{s,\infty}(\beta)$ by $V_K(\bold{f}_{\infty},\beta)$ (resp. $f_{1,p}(\beta),\ldots,f_{s,p}(\beta)$ by $V_K(\bold{f}_{p},\beta)$). In this article, under some assumptions for $\bold{f}_{\infty}$ (resp. $\bold{f}_{p}$), we give an estimation of a lower bound of the dimension of $V_K(\bold{f}_{\infty},\beta)$ (resp. $V_K(\bold{f}_{p},\beta)$) (see Theorem~2.4 for Archimedean case and Theorem~8.6 for $p$-adic case). Applying our estimation, we give a lower bound of the dimension of the $K$-vector space spanned...

10. A Lower Bound of the Dimension of the Vector Space Spanned by the Special Values of Certain Functions

HIROSE, Minoru; KAWASHIMA, Makoto; SATO, Nobuo
Let $K$ be a number field. Fix a finite set of analytic functions $\bold{f}_{\infty}:=\{f_{1,\infty}(x),\ldots,f_{s,\infty}(x) \}$ defined on $\{x\in \mathbb{C} \mid |x|>1\}$ (resp. $\mathbb{C}_p$-valued functions $\bold{f}_{p}:=\{f_{1,p}(x),\ldots,f_{s,p}(x) \}$ defined on $\{x\in \mathbb{C}_p \mid |x|_p>1\}$). For $\beta\in K$, we denote the $K$-vector space spanned by $f_{1,\infty}(\beta),\ldots,f_{s,\infty}(\beta)$ by $V_K(\bold{f}_{\infty},\beta)$ (resp. $f_{1,p}(\beta),\ldots,f_{s,p}(\beta)$ by $V_K(\bold{f}_{p},\beta)$). In this article, under some assumptions for $\bold{f}_{\infty}$ (resp. $\bold{f}_{p}$), we give an estimation of a lower bound of the dimension of $V_K(\bold{f}_{\infty},\beta)$ (resp. $V_K(\bold{f}_{p},\beta)$) (see Theorem~2.4 for Archimedean case and Theorem~8.6 for $p$-adic case). Applying our estimation, we give a lower bound of the dimension of the $K$-vector space spanned...

11. Norm Conditions on Maps between Certain Subspaces of Continuous Functions

For a locally compact Hausdorff space $X$, let $C_0(X)$ be the Banach space of continuous complex-valued functions on $X$ vanishing at infinity endowed with the supremum norm $\|\cdot\|_X$. We show that for locally compact Hausdorff spaces $X$ and $Y$ and certain (not necessarily closed) subspaces $A$ and $B$ of $C_0(X)$ and $C_0(Y)$, respectively, if $T:A \longrightarrow B$ is a surjective map satisfying one of the norm conditions i) $\|(Tf)^s (Tg)^t\|_Y=\|f^s g^t\|_X$, or ii) $\|\, |Tf|^s+|Tg|^t\,\|_Y=\|\, |f|^s+|g|^t\, \|_X$, \noindent for some $s,t\in \mathbb{N}$ and all $f,g\in A$, then there exists a homeomorphism $\varphi: \mathrm{ch}(B) \longrightarrow \mathrm{ch}(A)$ between the Choquet boundaries of...

12. Norm Conditions on Maps between Certain Subspaces of Continuous Functions

For a locally compact Hausdorff space $X$, let $C_0(X)$ be the Banach space of continuous complex-valued functions on $X$ vanishing at infinity endowed with the supremum norm $\|\cdot\|_X$. We show that for locally compact Hausdorff spaces $X$ and $Y$ and certain (not necessarily closed) subspaces $A$ and $B$ of $C_0(X)$ and $C_0(Y)$, respectively, if $T:A \longrightarrow B$ is a surjective map satisfying one of the norm conditions i) $\|(Tf)^s (Tg)^t\|_Y=\|f^s g^t\|_X$, or ii) $\|\, |Tf|^s+|Tg|^t\,\|_Y=\|\, |f|^s+|g|^t\, \|_X$, \noindent for some $s,t\in \mathbb{N}$ and all $f,g\in A$, then there exists a homeomorphism $\varphi: \mathrm{ch}(B) \longrightarrow \mathrm{ch}(A)$ between the Choquet boundaries of...

13. Ravels Arising from Montesinos Tangles

FLAPAN, Erica; MILLER, Allison N.
A ravel is a spatial graph which is non-planar but contains no non-trivial knots or links. We characterize when a Montesinos tangle can become a ravel as the result of vertex closure with and without replacing some number of crossings by vertices.

14. Ravels Arising from Montesinos Tangles

FLAPAN, Erica; MILLER, Allison N.
A ravel is a spatial graph which is non-planar but contains no non-trivial knots or links. We characterize when a Montesinos tangle can become a ravel as the result of vertex closure with and without replacing some number of crossings by vertices.

15. The Growth Rates of Ideal Coxeter Polyhedra in Hyperbolic 3-Space

NONAKA, Jun; KELLERHALS, Ruth
In~[7], Kellerhals and Perren conjectured that the growth rates of the reflection groups given by compact hyperbolic Coxeter polyhedra are always Perron numbers. We prove that this conjecture holds in the context of ideal Coxeter polyhedra in $\mathbb{H}^3$. Our methods allow us to bound from below the growth rates of composite ideal Coxeter polyhedra by the growth rates of its ideal Coxeter polyhedral constituents.

16. The Growth Rates of Ideal Coxeter Polyhedra in Hyperbolic 3-Space

NONAKA, Jun; KELLERHALS, Ruth
In~[7], Kellerhals and Perren conjectured that the growth rates of the reflection groups given by compact hyperbolic Coxeter polyhedra are always Perron numbers. We prove that this conjecture holds in the context of ideal Coxeter polyhedra in $\mathbb{H}^3$. Our methods allow us to bound from below the growth rates of composite ideal Coxeter polyhedra by the growth rates of its ideal Coxeter polyhedral constituents.

17. On the Krull-Schmidt Decomposition of Mordell-Weil Groups

MACIAS CASTILLO, Daniel
Let $A$ be an abelian variety defined over a number field $k$ and $p$ a prime number. Under some natural and not-too-stringent conditions on $A$ and $p$ we show that certain invariants associated to Iwasawa-theoretic $p$-adic Selmer groups control the Krull-Schmidt decompositions of the $p$-adic completions of the groups of points of $A$ over finite extensions of $k$.

18. On the Krull-Schmidt Decomposition of Mordell-Weil Groups

MACIAS CASTILLO, Daniel
Let $A$ be an abelian variety defined over a number field $k$ and $p$ a prime number. Under some natural and not-too-stringent conditions on $A$ and $p$ we show that certain invariants associated to Iwasawa-theoretic $p$-adic Selmer groups control the Krull-Schmidt decompositions of the $p$-adic completions of the groups of points of $A$ over finite extensions of $k$.

19. On a Class of Epstein Zeta Functions

OMAR, Sami
X.-J.~Li gave in~[4] a criterion for the Riemann hypothesis in terms of the positivity of a set of coefficients. In this paper, we investigate exactly how the Li criterion for the Riemann hypothesis fails for a class of Epstein zeta functions. This enables to derive some interesting consequences regarding $c_K=\frac{h_K\log d_K}{\sqrt{d_K}}$ of a quadratic imaginary field $K$ of absolute discriminant $d_K$ and class number $h_K$. Similar results are stated for the period ratios of elliptic curves with complex multiplication.

20. On a Class of Epstein Zeta Functions

OMAR, Sami
X.-J.~Li gave in~[4] a criterion for the Riemann hypothesis in terms of the positivity of a set of coefficients. In this paper, we investigate exactly how the Li criterion for the Riemann hypothesis fails for a class of Epstein zeta functions. This enables to derive some interesting consequences regarding $c_K=\frac{h_K\log d_K}{\sqrt{d_K}}$ of a quadratic imaginary field $K$ of absolute discriminant $d_K$ and class number $h_K$. Similar results are stated for the period ratios of elliptic curves with complex multiplication.

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