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'''F-theory''' is a modified version of [[String theory]] in which a second [[time]] variable is added.  It allows string theorists to construct new, more realistic vacua in the form of F-theory compactified on elliptically fibered [[Calabi-Yau]] four-folds.  The letter "F" stands for "Father", like the "M" in [[M-theory]] is often taken to stand for "Mother".

'''F-theory''' is a modified version of [[String theory]] in which a second [[time]] variable is introduced.  It allows string theorists to construct new, more realistic vacua in the form of F-theory compactified on elliptically fibered [[Calabi-Yau]] four-folds.  The letter "F" stands for "Father", like the "M" in [[M-theory]] is often taken to stand for "Mother".