Complexified Minkowski spacetime (source code)

= Complexified Minkowski spacetime
{title2=$M_{\mathbb C}\cong\mathbb C^4$}

= Complexified Minkowski space
{synonym}

Allow the four affine Minkowski coordinates to take independent complex values, obtaining $M_{\mathbb C}\simeq\mathbb C^4$ with the holomorphic extension of the flat conformal metric. In two-spinor coordinates $x^{AA'}$, the metric is proportional to $\epsilon_{AB}\epsilon_{A'B'}dx^{AA'}dx^{BB'}$. The <twistor incidence relation> associates a <complex projective line> to each affine point; compactification adds the points at conformal infinity.