One did not speak of dinner with Andrey Andreyevitch Markov, only the probability of dinner. And that probability might change, of course, depending on whether the great man had taken lunch, or gone without since his usual breakfast of black tea, unripe cantaloupe, and potato knish, or snacked perhaps on a thick slice of that Ukrainian poppyseed cake which Maria Ivanova baked with such flourish. That recipe alone would have made her name in St. Petersburg—if her husband had ever allowed a crumb to leave the house.

But Markov was nothing if not meticulous. In my humble opinion, Poisson and Bernoulli were dabblers compared to my employer, mere recreational mathematicians who tackled theorems in the same fashion that some in our aristocracy gaze at planets or contemplate the tides. I can still remember that morning in his high-ceilinged office when I first understood the full range of his mastery. We had spent the initial hours of the workday correcting the proofs of a German translation of his treatise on algebraic polynomials, and the next in playing a spirited game of chess while simultaneously composing bawdy limericks at the expense of the Duke of Dundook — making free use of all the consonant potential therein — when Andrey Andreyevitch remarked on a recent error of mine.

“Pyotr Warrenisovitch,” he said, his voice a little gruff from rhyming, “how long have we known each other?”

As he knew that I knew that he was quite aware of the precise interval of our acquaintance—and because, not having breakfasted myself, I was feeling faintly reckless—I replied, “Why, since we first encountered differential equations at the Faculty of Mechanics and Mathematics, unless I am mistaken.”

“Then I have relied on your judgment for longer even than I have placed my faith in Maria Ivanova?”

“Perhaps a few months more, sir, if mi = E(xi), where m is the number of months.”

“Then how can it be that—in my letter to the Dissociated Press — you have misspelled the name of our own sonneteer, the father of our national literature? Has it not always been Aleksandr, without the e?”

I did not reply that Pushkin’s given name had, by long practice, been transliterated into English as “Alexander.” As a proofreader, I know my place among the lower orders, those essential forest invertebrates without which a mighty oak would be unthinkable. Instead, I looked across the desk at Maria Ivanova, engaged in knitting a doubly ruled hyperboloid. Although Markov was without question my master, Maria was my secret muse. On that day, her sturdy beauty seemed especially stout, as if she’d pulled her braids a little too tight.

“Madame,” I said, “do you consider that the independence of variables is a necessary condition for the validity of the law of large numbers?”

At this utterance, Markov began energetically scribbling on a sheet of paper, a chain of inequalities that seemed to generate themselves, one after the other, like the words of a novel in verse. He was that nimble, that disciplined. I quickly calculated, with no small relief, that copyediting this new work might keep me employed for a fortnight.

But the bulk of my attention remained on Maria Ivanova, mistress of poppyseeds, moderator of my heart. I will never forget the way she returned my glance, on that day of all days, when even that ordinarily haughty ceiling now seemed impossibly high. The look in her eyes told me that I would never be excluded from the Academy, like our friend Gorky, nor excommunicated from the Russian Orthodox Church, like Tolstoy. I would continue within my prescribed limits, another anonymous drone in an infinite sequence of drones. And she would respect me for that.

“Petya,” she said, without pausing at her knitting, “One cannot be deprived of that which one does not seek. Nevertheless,” she continued, endearingly dropping a stitch, “you must stay for dinner.”