126. CMB 2006 (vol 49 pp. 313)
127. CMB 2006 (vol 49 pp. 213)
128. CMB 2006 (vol 49 pp. 117)
 Levene, R. H.

A Double Triangle Operator Algebra From $SL_2(\R)$
We consider the w$^*$closed operator algebra $\cA_+$ generated
by the image of the semigroup $SL_2(\R_+)$ under a unitary representation
$\rho$ of $SL_2(\R)$ on the Hilbert~space $L_2(\R)$.
We show that $\cA_+$ is a reflexive operator algebra and
$\cA_+=\Alg\cD$ where $\cD$ is a double triangle subspace
lattice. Surprisingly, $\cA_+$ is also generated as a
w$^*$closed algebra by the image under $\rho$ of a strict
subsemigroup of $SL_2(\R_+)$.
Categories:46K50, 47L55 

129. CMB 2006 (vol 49 pp. 82)
 Gogatishvili, Amiran; Pick, Luboš

Embeddings and Duality Theorem for Weak Classical Lorentz Spaces
We characterize the weight functions
$u,v,w$ on $(0,\infty)$ such that
$$
\left(\int_0^\infty f^{*}(t)^
qw(t)\,dt\right)^{1/q}
\leq
C \sup_{t\in(0,\infty)}f^{**}_u(t)v(t),
$$
where
$$
f^{**}_u(t):=\left(\int_{0}^{t}u(s)\,ds\right)^{1}
\int_{0}^{t}f^*(s)u(s)\,ds.
$$
As an application we present a~new simple characterization of
the associate space to the space $\Gamma^ \infty(v)$, determined by the
norm
$$
\f\_{\Gamma^ \infty(v)}=\sup_{t\in(0,\infty)}f^{**}(t)v(t),
$$
where
$$
f^{**}(t):=\frac1t\int_{0}^{t}f^*(s)\,ds.
$$
Keywords:Discretizing sequence, antidiscretization, classical Lorentz spaces, weak Lorentz spaces, embeddings, duality, Hardy's inequality Categories:26D10, 46E20 

130. CMB 2005 (vol 48 pp. 481)
 Azagra, D.; Fabian, M.; JiménezSevilla, M.

Exact Filling of Figures with the Derivatives of Smooth Mappings Between Banach Spaces
We establish sufficient conditions on the shape of a set $A$
included in the space $\mathcal L _s^n(X,Y)$ of the $n$linear
symmetric mappings between Banach spaces $X$ and $Y$, to ensure
the existence of a $C^n$\nobreakdashsmooth
mapping $f\colon X \rightarrow Y$,
with bounded support, and such that $f^{(n)}(X)=A$, provided that
$X$ admits a $C^{n}$smooth bump with bounded $n$th derivative
and $\dens X=\dens \mathcal L ^n(X,Y)$. For instance, when $X$ is
infinitedimensional, every bounded connected and open set $U$
containing the origin is the range of the $n$th derivative of
such a mapping. The same holds true for the closure of $U$,
provided that every point in the boundary of $U$ is the end
point of a path within $U$. In the finitedimensional case, more
restrictive conditions are required. We also study the Fr\'echet
smooth case for mappings from $\mathbb R^n$ to a separable
infinitedimensional Banach space and the G\^ateaux smooth case
for mappings defined on a separable infinitedimensional Banach
space and with values in a separable Banach space.
Category:46B20 

131. CMB 2005 (vol 48 pp. 607)
 Park, Efton

Toeplitz Algebras and Extensions of\\Irrational Rotation Algebras
For a given irrational number $\theta$, we define Toeplitz operators with
symbols in the irrational rotation algebra ${\mathcal A}_\theta$,
and we show that the $C^*$algebra $\mathcal T({\mathcal
A}_\theta)$ generated by these Toeplitz operators is an extension
of ${\mathcal A}_\theta$ by the algebra of compact operators. We
then use these extensions to explicitly exhibit generators of the
group $KK^1({\mathcal A}_\theta,\mathbb C)$. We also prove an
index theorem for $\mathcal T({\mathcal A}_\theta)$ that
generalizes the standard index theorem for Toeplitz operators on
the circle.
Keywords:Toeplitz operators, irrational rotation algebras, index theory Categories:47B35, 46L80 

132. CMB 2005 (vol 48 pp. 455)
 Rychtář, Jan

On GÃ¢teaux Differentiability of Convex Functions in WCG Spaces
It is shown, using the BorweinPreiss variational principle
that for every continuous convex function $f$ on
a weakly compactly generated space $X$,
every $x_0\in X$ and every weakly compact convex symmetric set $K$ such that
$\cspan K=X$,
there is a point of G\^ateaux differentiability of $f$ in $x_0+K$.
This extends a Klee's result for separable spaces.
Keywords:GÃ¢teaux smoothness, BorweinPreiss variational principle,, weakly compactly generated spaces Category:46B20 

133. CMB 2005 (vol 48 pp. 340)
 Andruchow, Esteban

Short Geodesics of Unitaries in the $L^2$ Metric
Let $\M$ be a type II$_1$ von Neumann algebra, $\tau$ a trace in $\M$,
and $\l2$ the GNS Hilbert space of $\tau$. We regard the unitary group
$U_\M$ as a subset of $\l2$ and characterize the shortest smooth
curves joining two fixed unitaries in the $L^2$ metric. As a
consequence of this we obtain that $U_\M$, though a complete (metric)
topological group, is not an embedded riemannian submanifold of $\l2$
Keywords:unitary group, short geodesics, infinite dimensional riemannian manifolds. Categories:46L51, 58B10, 58B25 

134. CMB 2005 (vol 48 pp. 251)
 Murphy, G. J.

The Index Theory Associated to a NonFinite Trace on a $C^\ast$Algebra
The index theory considered in this paper, a
generalisation of the classical Fredholm index theory, is obtained
in terms of a nonfinite trace on a unital $C^\ast$algebra. We relate
it to the index theory of M.~Breuer, which is developed in a
von~Neumann algebra setting, by means of a representation theorem.
We show how our new index theory can be used to obtain an index
theorem for Toeplitz operators on the compact group $\mathbf{U}(2)$,
where the classical index theory does not give any interesting result.
Categories:46L, 47B35, 47L80 

135. CMB 2005 (vol 48 pp. 283)
 Thibault, Lionel; Zagrodny, Dariusz

Enlarged Inclusion of Subdifferentials
This paper studies the integration of inclusion of subdifferentials. Under
various verifiable conditions, we obtain that if two proper lower
semicontinuous functions $f$ and $g$ have the subdifferential of $f$
included in the $\gamma$enlargement of the subdifferential of $g$, then
the difference of those functions is $ \gamma$Lipschitz over their
effective domain.
Keywords:subdifferential,, directionally regular function,, approximate convex function,, subdifferentially and directionally stable function Categories:49J52, 46N10, 58C20 

136. CMB 2005 (vol 48 pp. 161)
137. CMB 2005 (vol 48 pp. 69)
 Fabian, M.; Montesinos, V.; Zizler, V.

Biorthogonal Systems in Weakly LindelÃ¶f Spaces
We study countable splitting of Markushevich bases in weakly Lindel\"of
Banach spaces in connection with the geometry of these spaces.
Keywords:Weak compactness, projectional resolutions,, Markushevich bases, Eberlein compacts, Va\v sÃ¡k spaces Categories:46B03, 46B20., 46B26 

138. CMB 2005 (vol 48 pp. 97)
 Katavolos, Aristides; Paulsen, Vern I.

On the Ranges of Bimodule Projections
We develop a symbol calculus for normal bimodule maps over a masa
that is the natural analogue of the Schur product theory. Using
this calculus we are easily able to give a complete description of
the ranges of contractive normal bimodule idempotents that avoids
the theory of J*algebras.
We prove that if $P$ is a normal
bimodule idempotent and $\P\ < 2/\sqrt{3}$ then $P$ is a
contraction. We finish with some attempts at extending the symbol
calculus to nonnormal maps.
Categories:46L15, 47L25 

139. CMB 2005 (vol 48 pp. 50)
 Elliott, George A.; Gong, Guihua; Li, Liangqing

Injectivity of the Connecting Maps in AH Inductive Limit Systems
Let $A$ be the inductive limit of a system
$$A_{1}\xrightarrow{\phi_{1,2}}A_{2}
\xrightarrow{\phi_{2,3}} A_{3}\longrightarrow \cd
$$
with $A_n =
\bigoplus_{i=1}^{t_n} P_{n,i}M_{[n,i]}(C(X_{n,i}))P_{n,i}$, where
$~X_{n,i}$ is a finite simplicial complex, and $P_{n,i}$ is a
projection in $M_{[n,i]}(C(X_{n,i}))$. In this paper, we will
prove that $A$ can be written as another inductive limit
$$B_1\xrightarrow{\psi_{1,2}} B_2
\xrightarrow{\psi_{2,3}} B_3\longrightarrow \cd $$
with $B_n =
\bigoplus_{i=1}^{s_n} Q_{n,i}M_{\{n,i\}}(C(Y_{n,i}))Q_{n,i}$,
where $Y_{n,i}$ is a finite simplicial complex, and $Q_{n,i}$ is a
projection in $M_{\{n,i\}}(C(Y_{n,i}))$, with the extra condition
that all the maps $\psi_{n,n+1}$ are \emph{injective}. (The
result is trivial if one allows the spaces $Y_{n,i}$ to be
arbitrary compact metrizable spaces.) This result is important
for the classification of simple AH algebras (see
\cite{G5,G6,EGL}. The special case that the spaces $X_{n,i}$ are
graphs is due to the third named author \cite{Li1}.
Categories:46L05, 46L35, 19K14 

140. CMB 2004 (vol 47 pp. 540)
 Jain, Pankaj; Jain, Pawan K.; Gupta, Babita

Compactness of HardyType Operators over StarShaped Regions in $\mathbb{R}^N$
We study a compactness property of the operators between weighted
Lebesgue spaces that average a function over certain domains involving
a starshaped region. The cases covered are (i) when the average is
taken over a difference of two dilations of a starshaped region in
$\RR^N$, and (ii) when the average is taken over all dilations of
starshaped regions in $\RR^N$. These cases include, respectively,
the average over annuli and the average over balls centered at origin.
Keywords:Hardy operator, HardySteklov operator, compactness, boundedness, starshaped regions Categories:46E35, 26D10 

141. CMB 2004 (vol 47 pp. 615)
 Randrianantoanina, Narcisse

$C^*$Algebras and Factorization Through Diagonal Operators
Let $\cal A$ be a $C^*$algebra and $E$ be a Banach space with
the RadonNikodym property. We prove that if $j$ is an embedding
of $E$ into an injective Banach space then for every absolutely
summing operator $T:\mathcal{A}\longrightarrow E$, the composition
$j \circ T$ factors through a diagonal operator from $l^{2}$ into
$l^{1}$. In particular, $T$ factors through a Banach space with
the Schur property. Similarly, we prove that for $2
Keywords:$C^*$algebras, summing operators, diagonal operators,, RadonNikodym property Categories:46L50, 47D15 

142. CMB 2004 (vol 47 pp. 553)
 Kerr, David

A Geometric Approach to VoiculescuBrown Entropy
A basic problem in dynamics is to identify systems
with positive entropy, i.e., systems which are ``chaotic.'' While
there is a vast collection of results addressing this issue in
topological dynamics, the phenomenon of positive entropy remains by and
large a mystery within the broader noncommutative domain of $C^*$algebraic
dynamics. To shed some light on the noncommutative situation we propose
a geometric perspective inspired by work of Glasner and Weiss on
topological entropy.
This is a written version of the author's talk
at the Winter 2002 Meeting of the Canadian Mathematical Society
in Ottawa, Ontario.
Categories:46L55, 37B40 

143. CMB 2004 (vol 47 pp. 481)
 Bekjan, Turdebek N.

A New Characterization of Hardy Martingale Cotype Space
We give a new characterization of Hardy martingale cotype
property of complex quasiBanach space by using the existence of a
kind of plurisubharmonic functions. We also characterize the best
constants of Hardy martingale inequalities with values
in the complex quasiBanach space.
Keywords:Hardy martingale, Hardy martingale cotype,, plurisubharmonic function Categories:46B20, 52A07, 60G44 

144. CMB 2004 (vol 47 pp. 445)
 Pirkovskii, A. Yu.

Biprojectivity and Biflatness for Convolution Algebras of Nuclear Operators
For a locally compact group $G$, the convolution product on
the space $\nN(L^p(G))$ of nuclear operators was defined by Neufang
\cite{Neuf_PhD}. We study homological properties of the convolution algebra
$\nN(L^p(G))$ and relate them to some properties of the group $G$,
such as compactness, finiteness, discreteness, and amenability.
Categories:46M10, 46H25, 43A20, 16E65 

145. CMB 2004 (vol 47 pp. 206)
146. CMB 2004 (vol 47 pp. 108)
 Śliwa, Wiesław

On Universal Schauder Bases in NonArchimedean FrÃ©chet Spaces
It is known that any nonarchimedean Fr\'echet space of countable
type is isomorphic to a subspace of $c_0^{\mathbb{N}}$. In this
paper we prove that there exists a nonarchimedean Fr\'echet space
$U$ with a basis $(u_n)$ such that any basis $(x_n)$ in a
nonarchimedean Fr\'echet space $X$ is equivalent to a subbasis
$(u_{k_n})$ of $(u_n)$. Then any nonarchimedean Fr\'echet space
with a basis is isomorphic to a complemented subspace of $U$. In
contrast to this, we show that a nonarchimedean Fr\'echet space
$X$ with a basis $(x_n)$ is isomorphic to a complemented subspace
of $c_0^{\mathbb{N}}$ if and only if $X$ is isomorphic to one of
the following spaces: $c_0$, $c_0 \times \mathbb{K}^{\mathbb{N}}$,
$\mathbb{K}^{\mathbb{N}}$, $c_0^{\mathbb{N}}$. Finally, we prove
that there is no nuclear nonarchimedean Fr\'echet space $H$ with
a basis $(h_n)$ such that any basis $(y_n)$ in a nuclear
nonarchimedean Fr\'echet space $Y$ is equivalent to a subbasis
$(h_{k_n})$ of $(h_n)$.
Keywords:universal bases, complemented subspaces with bases Categories:46S10, 46A35 

147. CMB 2004 (vol 47 pp. 49)
 Lindström, Mikael; Makhmutov, Shamil; Taskinen, Jari

The Essential Norm of a Blochto$Q_p$ Composition Operator
The $Q_p$ spaces coincide with the Bloch space for $p>1$ and are
subspaces of $\BMOA$ for $0
Keywords:Bloch space, little Bloch space, $\BMOA$, $\VMOA$, $Q_p$ spaces,, composition operator, compact operator, essential norm Categories:47B38, 47B10, 46E40, 46E15 

148. CMB 2003 (vol 46 pp. 481)
 Bachir, M.; Lancien, G.

On the Composition of Differentiable Functions
We prove that a Banach space $X$ has the Schur property if and only if every
$X$valued weakly differentiable function is Fr\'echet differentiable. We
give a general result on the Fr\'echet differentiability of $f\circ T$, where
$f$ is a Lipschitz function and $T$ is a compact linear operator. Finally
we study, using in particular a smooth variational principle, the
differentiability of the semi norm $\Vert \ \Vert_{\lip}$ on various spaces
of Lipschitz functions.
Categories:58C20, 46B20 

149. CMB 2003 (vol 46 pp. 632)
 Runde, Volker

The Operator Amenability of Uniform Algebras
We prove a quantized version of a theorem by M.~V.~She\u{\i}nberg:
A uniform algebra equipped with its canonical, {\it i.e.}, minimal,
operator space structure is operator amenable if and only if it is
a commutative $C^\ast$algebra.
Keywords:uniform algebras, amenable Banach algebras, operator amenability, minimal, operator space Categories:46H20, 46H25, 46J10, 46J40, 47L25 

150. CMB 2003 (vol 46 pp. 588)
 Monteiro, Martha Salerno

Weakly Stable Relations and Inductive Limits of $C^\ast$algebras
We show that if $\mathcal{A}$ is a class of $C^\ast$algebras for which
the set of formal relations $\mathcal{R}$ is weakly stable, then $\mathcal{R}$
is weakly stable for the class $\mathcal{B}$ that contains $\mathcal{A}$ and
all the inductive limits that can be constructed with the $C^\ast$algebras in
$\mathcal{A}$.
A set of formal relations $\mathcal{R}$ is said to be {\it weakly stable\/} for
a class $\mathcal{C}$ of $C^\ast$algebras if, in any $C^\ast$algebra $A\in
\mathcal{C}$, close to an approximate representation of the set $\mathcal{R}$
in $A$ there is an exact representation of $\mathcal{R}$ in $A$.
Category:46L05 
