Zero weak gradient implies almost everywhere constant
128026
Weak derivatives equals zero
32064
Zero-dimensional matrices
147516
Continuous function whose right hand derivative equals 0 is constant?
19729
An infinite dimensional limit
24900
Homogeneity and Differentiability at $0$ implies linearity?
31672
$L^p$-norm of the gradient of a harmonic function.
9350
Gradient of Sobolev function on level sets
113343
$f$ is constant if derivative equals zero
776
Entire function with positive real part is constant (no Picard)
61190
If all derivatives of $f$ are uniformly bounded by a common constant and $f(1/n) = 0$ for all $n$, is $f$ identically zero?
119947
Can a non-zero vector have zero image under every linear functional?
130180
Smooth function with all derivatives zero
26740
Showing that asymptotic normality implies consistency.
15924
Convexity and strong lower semicontinuity imply weak lower semicontinuity
94489
Mean value property implies harmonicity
134136
Does weak convergence imply $L^2$-norm convergence?
32458
Does the rank-nullity theorem hold for infinite dimensional $V$?