in Minkowksi, the set of all possible null rays from a point defines a cone (light cone).(adsbygoogle = window.adsbygoogle || []).push({});

Now imagine I change the signature of Minkowski from (-,+,+,+) to (-,-,+,+) i.e. a space with two timelike directions and a metric ##ds^2=-dx_1^2-dx_2^2+dx_3^2+dx_4^2##. What kind of surface would the set of null rays form? Is it still a cone? Or is it something else?

Thanks

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# Light Cone Analogue

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