Which of these Banach spaces are Hilbert spaces?
121106
Parallelogram law valid in banach spaces?
19294
‎If ‎‎$‎X$ is an infinite-dimensional Banach space and ‎‎$‎‎u‎\in ‎B(X)‎$ ,then $\bigcap_{v\in K(X)}\sigma(u+v) =\cdots$
51177
When are two norms equivalent on a Banach space?
96717
Hahn-Banach Theorem for separable spaces without Zorn's Lemma
63285
Prove that this space is not Banach
144112
Show that $c_0$ is a Banach space with the norm $\rVert \cdot \lVert_\infty$
95887
How to show that quotient space $X/Y$ is complete when $X$ is Banach space, and $Y$ is a closed subspace of $X$?
8314
I am trying to find a Banach Space X and a singular operator (Infinite Dimensional Space)
114510
Inner Product Spaces
126744
Is any Banach space a dual space?
130045
Show that $l^2$ is a Hilbert space
87655
Consequence of the Hahn-Banach Theorem
55691
Are states of a quantum system represented by vectors in a Hilbert space?
154625
$\operatorname{span}(x^0, x^1, x^2,\cdots)$ and the vector space of all real valued continuous functions on $\Bbb R$
148001
In Hilbert space: $x_n → x$ if and only if $x_n \to x$ weakly and $\Vert x_n \Vert → \Vert x \Vert$.
104607
Hahn-Banach theorem, dual space
95074
Separability of $l^{p}$ spaces