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visits member for 4 years, 3 months
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As of August 2011 I am an assistant professor of mathematics at Loras College in Dubuque, Iowa, USA.


2h
comment Is a contractive algebraic homomorphism between unital $ C^{*} $-algebras a unital $ C^{*} $-algebraic homomorphism?
True, but I think the main point that joker is overlooking is that it must be proved that the map is in fact a $*$-homomorphism.
2h
comment Is a contractive algebraic homomorphism between unital $ C^{*} $-algebras a unital $ C^{*} $-algebraic homomorphism?
"I know that as $\Phi$ is linear, it respects the $*$-operations." What is the logic here? You need to use the contractive hypothesis to show it respects the $*$-operations; that is the whole point of the exercise, and it is not implied by linearity alone.
9h
comment Will it become impossible to learn math?
But one of the Mikes (1035813) gets pinged for every comment on this answer, so the experiment would have to be repeated on a thread neither "owns".
1d
comment The set of differentiability of an extension from half-plane to the plane
Are you planning to answer this one? If not, did you have thoughts on the problem?
1d
comment Prove determinant is zero
What did you get from row operations? Subtracting the first row from each of the other 2 rows is the first thing I would guess, and that leaves the last 2 rows linearly dependent.
Nov
21
awarded  Nice Answer
Nov
21
reviewed Close Solving Trig Equations Using Identities
Nov
21
reviewed Close Do I use induction or is there another way to prove $\binom{r}{r}+\binom{r+1}{r}+\cdots+\binom{n}{r}=\binom{n+1}{r+1}$?
Nov
21
reviewed Close Assume that we have assessed probability distributions for two discrete uncertain quantities
Nov
21
reviewed Close Prove that $A \times (B \cap C) = (A \times B) \cap (A \times C)$
Nov
21
answered Typo in Murphy's book: $ \sigma_A(b)= \sigma_B(b) \cup \{0\}$ or $ \sigma_A(b) \cup \{0\}= \sigma_B(b) \cup \{0\}$
Nov
19
comment Is $\nabla$ a vector?
Who are the authors of the book?
Nov
19
comment How the derivative might fail to exist
OK. I suppose this isn't the place to convince you that tangents are helpful, so I'll stop.
Nov
19
comment How the derivative might fail to exist
@Timbuc: Tangent lines to a curve and asymptotes are very different.
Nov
19
awarded  Nice Answer
Nov
19
awarded  Enlightened
Nov
19
awarded  Nice Answer
Nov
19
answered How the derivative might fail to exist
Nov
19
comment How the derivative might fail to exist
@Amanda: Why are you claiming it doesn't satisfy the condition?
Nov
19
comment How the derivative might fail to exist
@Timbuc: That is incorrect. $\sqrt[3]{x}$, if defined on $\mathbb R$ to be the inverse of $x^3$, does have a vertical tangent at $(0,0)$. Same is true if you multiply it by $3(x+2)$.