And he’s some sort of genius mathematician, too, Shlomi added. Collaborated with Erdős himself. The guy has an Erdős number of one.

Who the heck is Erdős? Tamar asks.

But Shlomi has to hang up, because, lo and behold, Dan has finally gotten through to Nepal.

3

That night Tamar doesn’t sleep well. It’s Friday, her daughter Iris is out late with friends, and on such nights Remy, only ten, likes to sleep in his mother’s bed. She can never fall asleep until Iris is safely at home, and as much as she likes Remy’s sweet presence, he’s a mouth breather, and his hot skinny legs are always shifting under the sheets. Yet even after Iris is back in her own bed, not smelling of alcohol or cigarettes or weed, under the glowing sticker stars on her ceiling, and Remy has at last fallen into a place of stillness in the well of sleep, Tamar lies awake thinking about the Husband. What bothers her, she decides, is the idea of her mother being taken advantage of. As tough and sassy as she may be, she is still a seventy-three-year-old woman living on her own, who needs her son every time she has a maintenance problem in the apartment, and her daughter to sort out her bank statements. Her health is fine, thank God, but though her mind is still sharp, she’s become increasingly forgetful. She continues to teach Hebrew to Sudanese immigrants twice a week, but twice in the last month she’s misplaced her phone and had to have Shlomi backtrack through her day with her until luckily they located it both times, once at the counter of the Super Pharm, and once at Gordon Pool, where she swims twice a week and the lifeguards know her. After that, Tamar started to notice other lapses, too. She called her friend Katie, a neuroscientist, who told her not to worry, there was no reason to believe it was the onset of Alzheimer’s, it was just that the messenger in her frontal cortex that got sent to the hippocampus was growing a little slower, a little more tired. It wasn’t that the memory was eroded, it was all still very much there, but as the brain ages, the messenger sent to retrieve the memory gets weak and lazy, and sometimes lost along the way.