Solution to SDE

Theorem (Solution to SDE)

Let (Zt)t0(Z_{t})_{t\ge 0} be Rr\mathbb{R}^{r}-valued continuous semimartingale and let F:R+×RdMd,r(R)F:\mathbb{R}^{+}\times \mathbb{R}^{d}\to\mathscr{M}_{d,r}(\mathbb{R}) be s.t. k>0\exists k>0 s.t. F(t,x)F(t,x)KxxtR+,x,xRd\lVert F(t,x)-F(t,x') \rVert \le K\lVert x-x' \rVert \quad\forall t\in\mathbb{R}^{+},\forall x,x'\in\mathbb{R}^{d}and tF(t,x)t\mapsto F(t,x) is locally bounded xRd\forall x\in\mathbb{R}^{d}. Consider the SDE dXt=F(t,Xt)dZt,X0=xRd(*)\tag{*}dX_{t}=F(t,X_{t})dZ_{t},\quad X_{0}=x\in\mathbb{R}^{d}Assume the filtration (Ft)t0(\mathcal{F}_{t})_{t\ge 0} satisfies the Usual conditions. Then: xR\forall x\in\mathbb{R}, !\exists ! up to indistinguishability a continuous (FtZ)t0(\mathcal{F}_{t}^{Z})_{t\ge 0}-adapted process (Xt)t0(X_{t})_{t\ge 0} satisfying ()(*).