$P(m)=P(\lambda)$.\
(c) The instability parabolic $P$ is generated by $T$ together with the root groups $U_\alpha$ correponding to roots $\alpha$ for which $\alpha(\lambda) \geq 0$.\
(d) A maximal torus $T$ in $G$ contains a instability 1-PS $\lambda$ for $m$ if and only if $T \subset
P(\lambda)$. Such a 1-PS is neccessarily unique.\
(e) For a non-semistable $m \in M$, if $\lambda(t)$ is an instability 1-PS of $m$, then $g\lambda(t)g^{-1}$ is the instability 1-PS of $gm$ and $\nu(\lambda,m)= \nu(g\lambda g^{-1},gm)$\
(f) For a 1-PS $\lambda$ of $G$ and any element $g \in P(\lambda)$ we have $\nu(m,\lambda)=\nu(gm,\lambda)$.\
(g) For any $g \in G$, we have $P(gm)=gP(m)g^{-1}$.\
(h) If $m \in M$ is an unstable point for the action of $G$ having an instability 1-PS defined over an extension field $[L:K]$, then the instability parabolic $P(m)$ is also defined over $L$.\
Now let $K$ be an arbitrary field (not neccessarily algebraically closed). Let $K_s$ denote its seperable closure. Let $G$ be a reductive algebraic group defined over $K$. Let $T$ be a fixed maximal torus of $G$ (which will always be split over $K_s$, in fact over a finite extension of K). Let $M$ be a projective variety defined over $K$ on which 