If $x$ and $y\in\mathbb R$ are computable, is $x+y$ computable?
130149
Computablility of a real number
34343
Determine all $f : \mathbb R \rightarrow \mathbb R$ such that $f(f(x) + y) = f(x^2 - y) + 4yf(x)$.
29679
Prove: $|x-y|\leq |x|+|y|$
84114
Does there exist a surjective homomorphism from $(\mathbb R,+)$ to $(\mathbb Q,+)$ ?
108742
Proving commutativity of addition for vector spaces
57089
Class of functions computable by Coq
14849
Decidability of a predicate.
130297
$A$ be a subset of $[0,1]$ with non-empty interior ; then is it true that $\mathbb Q+A=\mathbb R$?
3902
Does $k+\aleph_0=\mathfrak{c}$ imply $k=\mathfrak{c}$ without the Axiom of Choice?
78225
Countable additivity implies countable subadditivity?
69166
Cardinality of $\mathbb{R}$ and $\mathbb{R}^2$
92290
For each $x,y,z∈\mathbb N$, if $x<y$ then $x+z<y+z$
49240
$\forall x,y \in \mathbb{R}:\vert\cos x- \cos y\vert\leq\vert x-y\vert$
139992
Is power-associativity finitely axiomatizable?
74713
Show that for any natural numbers, if $S(x)=S(y)$ then $x=y$.
34693
Prove $E^{\mathbb Q}[Y]=E^{\mathbb P}[XY]$ if $E^{\mathbb P}[X]=\mathbb P(X>0)=1$ and $ \mathbb Q(A)=E^{\mathbb Q}[X1_A] $
15354
Formal proof of $\exists x \forall y P(x,y) \implies \forall y \exists x P(x,y)$