Yes. ImprovementDefs.xml has this for Gaia Vortex
<Prerequ>
<Techs>
<Option>GaiaTheory</Option>
</Techs>
</Prerequ>
However, in ThalanTechDefs.xml the internal name of the tech is <InternalName>ThalanGaiaTheory</InternalName> making it not able to be built. These 2 things need to match.
Edit: Although the generic name of the tech is GaiaTheory so I may be wrong. I never have figured out where the generic names of things can be used rather than the internal name since it doesn't seem to be everywhere.