hubieron existido
-they/you had existed
Preterite perfectellos/ellas/ustedesconjugation ofexistir.

existir

Hablando en general, en la TER el método de comparación de los fenómenos en dos diferentes sistemas inerciales presupone que ambos sistemas hubieron existido infinitamente.
Generally speaking, in SRT the method of comparison of the phenomena in two various inertial systems supposes, that both these systems have existed for infinitely long time.
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