Proving we can partition $\Bbb R^+$ into two sets which are closed under addition and Zorn's lemma
33040
Using Zorn's lemma show that $\mathbb R^+$ is the disjoint union of two sets closed under addition.
144572
Proof that ideals in $C[0,1]$ are of the form $M_c$ that should not involve Zorn's Lemma
139078
Infinite partition of $\mathbb N$ by infinite subsets
29403
Finding functions $f: \Bbb R_*^+ \to \Bbb R_*^+$ with certain properties
56010
Strengthening of a lemma in Ramsey Theory: $R(m, n) \le R(m-1, n) + R(m, n-1)-1$ if both numbers are even
133884
A proof using Yoneda lemma
6410
Prove that $(ma, mb) = |m|(a, b)\ $ [GCD & LCM Distributive Law]
36044
Show $\Bbb R ^n$ with a finite set removed is still connected.
95244
Prove that a finite union of closed sets is also closed
69337
Zorn's Lemma And Axiom of Choice
76049
Prove that if $a|b$ and $a|c$ then $a|(sb+tc)$ for all $s, t \in \mathbb{Z}$
151544
Prove that if $B$ is the set of rationals in $[0,1]$ with a finite subcover, then: $1 \leq \sum_{k=1}^n m^*(I_k)$
59885
Proof Verification - Every sequence in $\Bbb R$ contains a monotone sub-sequence
9268
Proving that the Union of Two Compact Sets is Compact
72551
Proof that $\rho = \pm1$ implies linear combination
13906
How to prove the set $S$ is closed under the binary operation $a*b=a+b+kab$?
41726
Musical and combinatorial proof