Mathematicians are divided on the definition of “equal,” posing a challenge

In the equation “2 + 2 = 4”, what does the “=” mean? This is actually a complicated question, as mathematicians don’t agree on the definition of what makes two things equal. This debate has been quietly simmering for decades, but recent efforts to make mathematical proofs verifiable by computer programs (formalization) have given the discussion new importance.

“Mathematicians use equations in two different ways, and I’m fine with that,” says…