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Dec
12
comment Weak time derivative for functions $u \in L^2(0,T;L^2(\Omega))$
Who said you can't?
Dec
10
comment Which of the following is always true for A and B
You have a small mistake in C.
Dec
9
comment Norm of linear functional in $W^{1,2}$
It depends on the norm in $W^{1,2}$. Where does the $f$ in your estimate has gone?
Dec
9
comment Is there a proof of subdifferential sum rule that doesn't use duality theory?
Then you could post your proof as an answer. I feel, however, that (in infinite dimension) any proof has to use Hahn-Banach (or the AC) at some point. Hence, it is not possible by only using the inequalities.
Dec
8
revised Proof that $n^n<(n!)^2$ for $n>2$
this is not functional analysis
Dec
6
comment On existence of an element whose is orthogonal with given $n$ elements of a Hibert space of infinite dimension
Sounds like homework. What have you tried?
Dec
6
comment Is there a proof of subdifferential sum rule that doesn't use duality theory?
What do you mean by "duality theory"? The sum-rule can be understood as a separation theorem of the epigraphs of $f$ and $g$. Does such a approach satisfy "without duality theory"?
Dec
4
comment Compactness of a sequence
What is a compact sequence?
Dec
4
comment How to get the perfect square for the following equation
Maybe you want to give a reference for that paper? Is there some structure in $A$?
Dec
4
answered Local optimality of a KKT point.
Dec
4
answered How to get the perfect square for the following equation
Nov
28
answered Choosing a clever “test function” in Sobolev spaces.
Nov
28
comment The space of distribution $H^{-1}$
Please check your question. The identity looks like integration by parts, but you do not integrate w.r.t. time. Is this intended?
Nov
28
answered Weak-* convergence in Sobolev spaces
Nov
28
answered Strongly convergent to zero in $L^2$ but $H^1$ norm not vanishing
Nov
28
comment for a compact manifold $M$, is the dual space of $H^1(M)$ equal to $H^{-1}(M)$?
How do you define $H^{-1}(M)$? Typically, one has $(H_0^1(M))* = H^{-1}(M)$.
Nov
21
comment Which is the better way to optimize a function with 3 variables
In any case, you should add a line search, see en.wikipedia.org/wiki/Line_search and en.wikipedia.org/wiki/Backtracking_line_search.
Nov
20
answered The polar of a set: Importance and Applications
Nov
20
comment Why is the conjugate direction better than the negative of gradient, when minimizing a function
This answer is not true. In the special case that $A$ is the identity, CG (and steepest descent) will finish in only one step. After your transformation $T$, however, CG will take two steps.
Nov
15
answered Two versions of Lax-Milgram theorem