4 What does $φ(a) = a$ mean in this statement? 3 Prove that $5$ is irreducible in $\mathbb Z[\sqrt{2}]$ 2 On $\int_0^{2\pi}e^{\cos2x}\cos(\sin2x)\ \mathrm{d}x=2\pi$ 2 Question regarding elementary set proof 2 Questions about Cauchy's thm. on complex integration

### Reputation (459)

 +40 When is the group $C^*$-algebra of a locally compact group an AF-algebra? +10 Questions about Cauchy's thm. on complex integration +10 Prove that $5$ is irreducible in $\mathbb Z[\sqrt{2}]$ +2 The distance of a vector to a subspace

### Questions (4)

 5 Constructing an Infinite Family of Graphs 4 When is the group $C^*$-algebra of a locally compact group an AF-algebra? 1 Find the residue of the function $f(z) = \frac{z^3}{(z-1)(z^4+2)}$ at $z=0$ 0 Is there a correspondence between different hyperbolic automorphisms of a regular tree?

### Tags (35)

 10 abstract-algebra × 4 4 ring-isomorphism 7 ring-theory × 2 3 unique-factorization-domains 4 polynomials × 2 2 complex-analysis × 2 4 real-analysis × 2 2 complex-integration 4 irreducible-polynomials 2 cauchy-integral-formula

### Bookmarks (35)

 430 Proofs that every mathematician should know. [closed] 280 Is mathematics one big tautology? 242 Can you answer my son's fourth-grade homework question: Which numbers are prime, have digits adding to ten and have a three in the tens place? 158 Induction on Real Numbers 151 What's new in higher dimensions?