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<div style="font-family:sans-serif"><div style="white-space:normal"><p dir="auto">Isadore Singer died last month. He was born in 1924.</p>
<p dir="auto">In my mind I keep a short list of great mathematicians who were also exceptional human beings. Singer is one; another is my thesis advisor Don Spencer. There is a good obituary at quantamagazine.org. Although we never worked together, he was always warm and friendly even on those occasions after one or more decades since we had seen each other.</p>
<p dir="auto">I recommend the obituary.</p>
<p dir="auto">—Barry</p>
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