Why are we allowed to decompose a function of two variables $f(x,y)$ into the form $\sum_n^\infty c_n(y)\psi_n(x)$?
98363
Expanding two-variable function $f(x,y)$ over the complete sets $\{ g_{i}(x) \}$ and $\{ h_{j}(y) \}$
71945
How to reduce circuit elements of a decomposed $C^2(U)$ operation?
45220
Proving the sum of two independent Cauchy Random Variables is Cauchy
127052
Independence of non-constant real variables
107772
Separability of functions with compact support
49994
Deduction of $\forall y \exists x (x=y)$
78075
Why can I apply $HS^\dagger$ and then measure in the computational basis to measure $Y$?
62504
Is there any known relationship between $\sum_{i=1}^{n} f(i)$ and $\sum_{i=1}^{n} \dfrac {1}{f(i)}$
145447
bilinear form - proof
157744
Cauchy's functional equation with composite function: $gf(x+y)=gf(x)+gf(y)$
103251
Solution(s) to $f(x + y) = f(x) + f(y)$ (and miscellaneous questions...)
142256
Polygamma function series: $\sum_{k=1}^{\infty }\left(\Psi^{(1)}(k)\right)^2$
147978
Limits using epsilon delta definition $f(x,y)=xy$ for functions of two variables
65661
Decomposition of a homogeneous polynomial
106799
Proof Verification: Converse of Intermediate Value Theorem
20568
Does the following have a solution for f(x,y)?
146152
Characterising functions $f$ that can be written as $f = g \circ g$?