Comment by Erem

From Wikipedia, imaginary numbers...

> Originally coined in the 17th century by René Descartes[4] as a derogatory term and regarded as fictitious or useless, the concept gained wide acceptance following the work of Leonhard Euler in the 18th century, and Augustin-Louis Cauchy and Carl Friedrich Gauss in the early 19th century.

I think the jury is still out wrt utility of AdS spaces. They could be useless toys, or they could be in the Descartes phase rn.