At Lange Gasse 72 in Vienna’s 8th district, as well as at Währingerstraße 33–35 in the 9th district, memorial plaques commemorate the mathematician Kurt Gödel, who lived at these addresses between 1927 and 1929 and took part in meetings of the Vienna Circle. There are indications of a mutual reception between Gödel and Ludwig Wittgenstein, both of whom explored the philosophical foundations of mathematics. However, there is no evidence of a personal encounter between the two.

Source: Monk, R. (1991). Ludwig Wittgenstein: The Duty of Genius. Vintage.