Ho(Cat) has pullbacks.
Некорректный пример в NLab:
https://ncatlab.org/nlab/show/Ho(Cat)
Объяснение на mathoverflow:
https://mathoverflow.net/questions/512690/example-of-a-fibre-product-that-does-not-exist-in-mathrmho-mathbfcat/512698#512698
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