Friedrich Hayek had to flee when the London School of Economics was moved to Cambridge during World War II (his friend and intellectual rival John Maynard Keynes apparently helped him find accommodations).

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What matters most is not the closely drawn intellectual argument about rival policy platforms, but the body language and the pithy one-liner that sums up an opponent's faults.

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Also on Motorola's list of potential troubles: its intellectual property spat with rival Research In Motion and its postponed plan to split up the company, reportedly because buyers' bids did not meet expectations.

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The nine-person jury at the federal court in San Jose, California had to consider 700 questions about each side's claim that its rival had infringed its intellectual property.

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They became a focus for intellectual life and could be seen as an implicit rival to the mosque as a meeting place.

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But his rival and, some would argue, intellectual superior, Nikola Tesla , spent his last years feeding pigeons outside New York's Public Library, and died nearly penniless.

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But the similarities with Facebook are beside the point, says StudiVZ, which is accusing its larger rival of using the pretence of protecting its intellectual property rights to make up for its failure to succeed in Germany.

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Both Mr Lafontaine and Mr Hombach published books on economics last year and they read, respectively, like rival tracts by Keynes and Milton Friedman (albeit with a mite less intellectual rigour in both cases).

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