T. Eskin
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 Apr 14 reviewed Reject Is there a symbol for always less than (or just always?) Apr 14 reviewed Edit Convergence of a complex series for some values of z Apr 14 revised Convergence of a complex series for some values of z notation issues Apr 14 reviewed Reject Problem with differential equation,someone to give hint? Apr 14 reviewed Approve Is there a symbol for always less than (or just always?) Apr 14 reviewed Edit Is there a symbol for always less than (or just always?) Apr 14 revised Is there a symbol for always less than (or just always?) formatting Apr 13 answered Is this outer measure really regular? Apr 13 comment Is this outer measure really regular? What you have showed is that $\overline{\mathbb{S}}=\{\emptyset,X\}$. Does this violate outer-regularity? Apr 13 comment Proving that a certain function is well-defined For $T$ to be well defined you need to show that $Tf$ is a continuously differentiable function for any continuous $f$. I.e. $Tf\in C^1[0,1]$ for any $f\in C[0,1]$. But this is implied by the fundamental theorem of calculus as the answers below indicate. Apr 11 answered How do I show the series $\sum{\frac{1}{\log(n)^{\log(n)}}}$ converges? Apr 5 comment Prove that the vector space is 3D @copper. Great! you're welcome. Apr 5 comment Prove that the vector space is 3D @copper. Look up the definition for dimension. The dimension of a vector space is defined as the number of linearly independent vectors that spans it. Apr 5 comment Prove that the vector space is 3D @copper if $ax+be^{x}+c\sin(x)=0$ in $C(\mathbb{R})$ means that $ax+be^{x}+c\sin(x)$ is equal to the function that is zero everywhere. So this equation holds for all $x\in\mathbb{R}$. Now you can go ahead and choose your favorite $x$ values and plug them in to conclude that we must have $a=b=c=0$. I gave you one choice of such $x$ but there are plenty of other options for this. Apr 5 comment Prove that the vector space is 3D @copper $span\{x,e^{x},\sin(x)\}=\{ax+be^{x}+c\sin(x):a,b,c\in\mathbb{R}\}=V$ by definition of span and $V$. Apr 5 revised Prove that the vector space is 3D added 343 characters in body Apr 5 answered Prove that the vector space is 3D Apr 5 reviewed Approve How can I prove that column space of $A^2$ contained in the column space of $A$? Apr 3 reviewed Approve injective linear transformation basis. Mar 29 reviewed Reject Determinant of a symmetric, sparse matrix