Topic 4: Concepts of infinity: logic vs mathematics
Osnova sekce
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With the advent of forcing, concepts of infinity extended from "size", i.e., how hight a given infinity is in terms cardinals, to "width", i.e., to combinatorial properties making the universe wide in the low parts of the cumulative hierarchy. See the enclosed link for a review of "logical" and "mathematical" compactness principles (corresponding to infinity concepts).