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:
“This event advertises me that there is such a fact as death,—the possibility of a man’s dying. It seems as if no man had ever died in America before; for in order to die you must first have lived.”
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