From The Associated Press 7 May 2016:
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An Ivy League professor said his flight was delayed because a fellow passenger thought the math equations he was writing might be a sign he was a terrorist. American Airlines confirms that the woman expressed suspicions about University of Pennsylvania economics professor Guido Menzio. ...Menzio said he was flying from Philadelphia to Syracuse on Thursday night and was solving a differential equation related to a speech he was set to give at Queen's University in Ontario, Canada. He said the woman sitting next to him passed a note to a flight attendant and the plane headed back to the gate.
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