11,159 reputation
11230
bio website math.brown.edu/~lubinj
location Minnesota
age 77
visits member for 2 years, 6 months
seen 4 hours ago

Aged mathematician


Apr
16
revised General methods for solving p-adic inequality $|a^2+b|_{p}<p^{-k}$ for $a\in \mathbb{Z}$
clarification
Apr
14
revised $2$-adic inverse of $3$
Expanded considerably on my answewr, explaining a technique for $p$-adic hand computation.
Mar
20
revised Geometric meanings of hyperbolic cosinus and sinus
Made a long explanation from a primitive viewpoint of how to measure distance on the hyperbolic plane in a canonical way.
Mar
18
revised Basic Question on Field Theory - Hopefully to Illustrate Several Concepts
expanded to cover both parts of the question
Jan
18
revised Find basis of $\mathbb{Q}(\sqrt{2}+\sqrt[3]{4})$
corrected a sign error in the denominator of the last fraction
Dec
6
revised Why do we have to do the same things to both sides of an equation?
added 10 characters in body
Nov
20
revised Finding injective mapping $f : \{0,1,2\}^\mathbb{N} \rightarrow \{0,1\}^\mathbb{N}$
respond to OPs request for proof that the function is one-to-one
Nov
20
revised Finding injective mapping $f : \{0,1,2\}^\mathbb{N} \rightarrow \{0,1\}^\mathbb{N}$
Took me a long time to understand his attempted answer. Deleted my answer, and wrote out what he was looking for.
Nov
18
revised Compositum of finite field extensions
OP asked for a complete proof
Nov
6
revised Finite polynomial rings and degree of polynomial
changed “$x^5=x^0$” to $x^5\ne x^0$, which I’m sure was the respondent’s intention.
Oct
19
revised finding the inverse of function. the domain is given and the question requires to find the inverse.
Corrected a serious error and other problems arising from misreading the given question.
Oct
11
revised can a great circle route be predicted from initial condition?
corrected a serious and confusing typo, I once had $\lambda$ when I meant $\theta$
Sep
11
revised Why are the order-of-operations conventions good?
corrected a typo, turning an ungrammaticality into good language
Sep
1
revised Finding degree of $\mathbb{Q}(i, \sqrt{-1 + \sqrt{-3}}) : \mathbb{Q}$
Gave second argument showing that the field is the 24-th cyclotomic field.
Aug
29
revised The integer $c_n$ in $(1+4\sqrt[3]2-4\sqrt[3]4)^n=a_n+b_n\sqrt[3]2+c_n\sqrt[3]4$
added a clearer explanation
Aug
14
revised Minimal Polynomial Trouble
Explained my example in much greater detail.
Jul
21
revised Mirror anamorphosis for Escher's Circle Limit engravings?
added 1334 characters in body
May
3
revised Proving $e^{i\pi} = -1$ without proving $e^{ix} = \cos x + i\sin x$
added 2 characters in body
Apr
20
revised Prove $\sqrt[3]{3} \notin \mathbb{Q}(\sqrt[3]{2})$
added the second argument showing that the two fields are different.
Mar
21
revised Proof: if the graphs of $y=f(x)$ and $y=f^{-1}(x)$ intersect, they do so on the line $y=x$
Tightened up the proof at the end considerably, changing a proof by contradiction to a direct proof.