Order Theory
The answer to Suslin's problem is independent of ZFC. The diamond principle ◊ proves the existence of a Suslin line, while MA + ¬CH proves that no Suslin line exists.
Existence of Kurepa trees is independent of ZFC.
Read more about this topic: List Of Statements Undecidable In ZFC
Famous quotes containing the words order and/or theory:
“When a person hasn’t in him that which is higher and stronger than all external influences, it is enough for him to catch a good cold in order to lose his equilibrium and begin to see an owl in every bird, to hear a dog’s bark in every sound.”
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