a passage, so remarkable even to children by that memorative topic
Answering a question going back to Gromov, we show that, for an open, polyhedral contractible manifold M of dimension at least 6, the following conditions are equivalent: - M admits a geodesically complete CAT(0) metric; - M can be collapsed; - M is pseudocollarable. This yields many new contractible manifolds that admit CAT(0) metrics, and it shows that the CAT(0) property of a contractible manifold is purely determined by a condition at infinity, and shows that contractible manifolds of the Whitehead type can never admit a complete CAT(0) metric.
The hotel garden shrieked with bird life, and there were crocodiles in the courtyard pond; the fountains on either end of Cairo Road blustered with fresh water, and the street children were mad-eyed (those who can afford it sniff glue or gasoline, and those who can't sniff jenkem, fermented human sewage kept in a plastic bag for a week or so until it gives off intoxicating fumes).
a pryproof lock
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