One is the sheer magnitude of the underrepresentation of black academics in research math. According to the American Mathematical Society, there are 1,769 tenured mathematicians at the math departments of the 50 United States universities that produce the most math Ph.D.s. No one tallies the number of black mathematicians in those departments, but as best I can tell, there are 13. That comes to seven-tenths of 1 percent of the total — perhaps as far as any job classification gets from accurately reflecting the share of black Americans in the general adult population, which stands at 13 percent.

Maybe it seems like splitting already ludicrously fine hairs, but in biomedicine, the share of black scientists who receive major research grants from the National Institutes of Health (1.4 percent) is about twice as high as the share of black mathematicians on the tenured faculty of top United States math departments. The share of employees at Facebook who are black (4 percent) is roughly six times higher; the share of black graduates from United States medical schools (6 percent), nine times higher. Among the film and television agents at Hollywood’s top four talent agencies, according to a recent New York Times article, black agents number in the dozens, which makes their share roughly eight times that of the black mathematicians.

“To say that I feel isolated is an understatement,” Dr. Goins wrote.

Then there is the cost of that underrepresentation to the public. In the private sector, shareholders bear the opportunity lost by excluding demographic groups. But mathematics research is funded largely by taxpayers. Federal agencies distributed some $350 million in grants to American universities for basic math research alone in 2016. And math — “the queen of the sciences,” as the 19th-century mathematician Carl Friedrich Gauss is said to have labeled his discipline — underpins virtually all of the tens of billions of dollars worth of basic science research that Americans support each year.

“How much further forward might mathematics have gotten today,” Richard Taylor, a prominent (white) mathematician at Stanford, wrote in an email, “if we had attracted that talent? ”