In set theory, the ground axiom was introduced by Hamkins (2005) and Reitz (2007). It states that the universe is not a nontrivial set forcing extension of an inner model.
References
Ground axiom Wikipedia(Text) CC BY-SA
In set theory, the ground axiom was introduced by Hamkins (2005) and Reitz (2007). It states that the universe is not a nontrivial set forcing extension of an inner model.