<prompt> Bhala okuqhubekayo kwalesi sigaba - Ngemva kokuhlasela kweCzechoslovakia ngo-1968 yiWarsaw Pact  <response>: , wayengamukelwa ngezandla ezivulekile. Ngakho ngo-1971, wathuthela e-Ottawa, eCanada, lapho asungula khona futhi wahola khona umnyango wezibalo zesimanje eCarleton University oye waba nethonya elikhulu ezweni le-algebra, amathuba, nezibalo. 