Let $$u_m \rightharpoonup u$$ (weak convergence) in $X$, a Hilbert space.$$u_m \rightharpoonup u \quad \text{(weakly) in $L^\infty(0,T;L^2(\Omega)) \cap L^2(0,T;H^1(\Omega))$}.$$ We are given $f:X \to X$$f:\mathbb R \to \mathbb R$, a Lipschitz continuous invertible map which is monotone $$(f(x)-f(y),x-y) \geq 0\quad\text{for all $x, y$}$$$$(f(x)-f(y))(x-y) \geq 0\quad\text{for all $x, y$}$$ and we have $$f(u_m) \rightharpoonup f(v)$$ in$$f(u_m) \rightharpoonup f(v) \quad \text{in $L^2(0,T;H^1(\Omega))$}$$ for some $X$$v \in L^2(0,T;H^1(\Omega))$ (assume that for some $v \in X$$u \in L^2(0,T;H^1)$, $f(u)$ and $f^{-1}(u)$ are in $L^2(0,T;H^{1}(\Omega))$.)
How do IIs it possible to show that indeed $v=u$, i.e. $f(u_m) \rightharpoonup f(u)$? I can't seem to do it by using the monotonicity method.