2,798 reputation
925
bio website google.com
location New York, NY
age 94
visits member for 2 years, 4 months
seen 20 hours ago

I like fish! And agonizing over solving the Finite Sub-Cuddling hypothesis!

The chameleon, incidentally, says "Maaaaaaaaaaaaaaaaattthh!"


Apr
14
reviewed Reject suggested edit on Probability distribution of the product of random numbers
Apr
12
reviewed No Action Needed number cubic polynomials possible
Apr
12
reviewed No Action Needed irreducible polynomial of $\alpha$ over $\mathbb{Q}$ and $[\mathbb{Q}(\alpha):\mathbb{Q}]$.
Apr
12
reviewed Looks Good condition for roots of quartic equation to be purely imaginary
Apr
12
reviewed Approve suggested edit on Give an example of a function from $X$ to $Y$
Apr
9
revised Prove or disprove by definition the existence of the limit of $\lim_{n\to\infty}\sqrt[3]{n+1} - \sqrt[3]{n}$
added 4 characters in body; edited title
Apr
2
reviewed Approve suggested edit on What is the minimum value of $(\sin x + \cos x + \csc (2x))^3$
Apr
2
reviewed No Action Needed Integral from inverse Fouriertransform of 1/(1+p^2)^2
Apr
2
reviewed Approve suggested edit on What is the probability of rolling exactly 2 2's when rolling 5 dice?
Apr
2
revised Name for grammars with rules $A \to uA$
edited body
Apr
2
revised Name for grammars with rules $A \to uA$
edited body
Apr
2
answered Name for grammars with rules $A \to uA$
Mar
30
answered There is a sequence of operations on grammars of a string that strictly decreases the size of grammars down to the smallest grammer.
Mar
26
comment Mean absolute value of random walk with drift
(e.g., as done here for the case w/o drift (it amounts to the changed boundaries, and the '2' term you'll notice in the integral)). For the reflection principle, c., e.g., here.
Mar
26
comment Mean absolute value of random walk with drift
This is sloppy. Sigma isn't even defined as you talk about standard normal disturbances; and the result you quote as 'well-known fact' should probably have a t in the numerator, under the square root. Also, there seems uncertainty about whether you talk about a discrete (random walk) object, or a continuous one (integration - which, I am aware, makes sense for discrete objects, but is better referred to as summation). As to solving this after clarifying what you really want, use the "reflection principle"
Mar
25
revised What does it take to get a job at a top 50 math program in the U.S.?
deleted 33 characters in body
Mar
25
reviewed Approve suggested edit on surjective map and cardinality
Dec
17
awarded  Yearling
Dec
11
awarded  Nice Answer
Nov
19
comment Decompose $A$ as $A = LPU$,
They are though. Do you have Artin's book? At the bottom of proof I have it as an obvious lemma. So the proof works as is. I think it would help you most to carefully look at the def in book, and multiply a few, so it should become clear.