Standard symbol / notation for "x knows y", or the inverse What's the standard way to express "$x$ knows about $y$", or "$x$ has no knowledge of $y$" in cryptographic notation?

Example (PRNG predictor):

$\exists f : P(f(G(k)|_{0..n}) = G(k)|_{n+1}) \geq 0.5 + \epsilon$, for non negligable $\epsilon$, where $f$ has no knowledge of $k$.
The notation is "", i.e., the empty string. $\;\;$ Since $k$ is not an input of $f$, $f$ has no knowledge of $k$.