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PointfreeTopology

The lineage

Nobody does
this alone

Pointfree topology was assembled slowly, by a small and unusually generous community, across seventy years and several continents. Names in green have a page of their own.

Bernhard Banaschewski in a dark suit, seated in a carved wooden chair against a stone wall

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Read about Bernhard

1926–2022McMaster

He arrived in Hamilton, Ontario in 1955 and stayed for sixty-seven years. In that time he took pointfree topology from a handful of suggestive definitions to a theory that could stand beside the classical one — and in places replace it.

  1. Marshall H. Stone

    1903–1989 · Harvard · Chicago

    His 1936 representation theorem turned Boolean algebras into spaces, and spaces into algebra. Every later duality in the subject is a variation on that exchange.

  2. Charles Ehresmann

    1905–1979 · Paris

    Proposed in the 1950s that a lattice of opens is worth studying as a structure in its own right — the 'local lattices' that became frames.

  3. Hugh Dowker & Dona Papert Strauss

    1912–1982 · b. 1934 · London

    Carried frame theory from a definition into a working toolkit through the 1960s and 70s, including the treatment of sublocales and separation.

  4. John Isbell

    1930–2005 · Buffalo

    “Atomless parts of spaces” (1972) named the locale and insisted that the pointfree side was the better-behaved category, not a curiosity.

  5. Bernhard Banaschewski

    Full profile →

    1926–2022 · McMaster

    Over two hundred papers that made the pointfree theory complete: compactification, real-valued functions, rings, and proofs that need no choice.

  6. Christopher Mulvey

    b. 1944 · Sussex

    With Banaschewski, built the Stone–Čech compactification of locales and the localic form of Gelfand duality.

  7. Peter Johnstone

    b. 1948 · Cambridge

    Stone Spaces (1982) gave the field its canonical text; “The point of pointless topology” (1983) gave it its manifesto.

  8. Aleš Pultr

    b. 1938 · Charles University, Prague

    Banaschewski's long-running collaborator and, with Picado, author of the modern reference on frames and locales.

  9. Jorge Picado

    b. 1963 · Coimbra

    Co-author of Frames and Locales (2012) and a steady custodian of the subject's literature and history.