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May
8
comment The number of subsets of cardinality less than $\kappa$ of a cardinal $\kappa$ is $\kappa$
If $\kappa =\aleph_1$ then certainly $\#S\ge 2^{\aleph_0}$, which may be $>\kappa$.
May
8
comment Is there a special name for matrices $A^T A$ and $A A^T$?
How is "symmetric positive semi-dfinite" too general? Could you exhibit a symmetric positive semidefinite matrix that is not of this form?
May
8
revised Is there a special name for matrices $A^T A$ and $A A^T$?
edited tags
May
8
answered Supremum of a sequence of functions
May
8
comment Dust coating a length of road that is 1.25 miles long.
@RossMillikan For me as European that is precisely the hard part of it ...
May
8
answered Prove $(s_n)$ converges, where $s_{n+1} \lt r(s_n)$.
May
8
comment Finding value of the summation
@user2399614 There is no need to reconsider
May
8
reviewed Leave Closed Is $\phi$ convex if it is continuous and $\phi \Big(\frac{x+y}{2}\Big)\le \frac{1}{2}\phi (x) +\frac{1}{2} \phi (y)$
May
8
answered Is $\exp$ the only function satisfying $f(x)=\displaystyle \int_{-x}^{+\infty} f(-t) dt$?
May
8
answered Finding value of the summation
May
8
answered Interesting Power Series
May
8
answered How many poker hands have exactly one pair?
May
8
comment Mathematical structures with name reffering to a country
Catalan numbers ar not really an example because the name is derived from Eugène Charles Catalan
May
8
answered Prove that $ln(x)$ is concave by using the following definition for $ln(x)$
May
8
answered Accurate Formula and One Old-Exam Questions?!
May
7
answered How is it possible to have a function that is both bounded an entire?
May
7
comment Find some value of $n$ such that $|a_n - a| < 10^{-1000}$
You should rather find that $a_n\to 0$.
May
7
reviewed Looks OK How is this true? Bookworm puzzle
May
7
reviewed Looks OK Integration of $(\tan x\sec x)^3$
May
7
answered limits and continuity: irrational and rational piecewise function