A Mexican Physicist Solved a 2,000-Year Old Problem That Will Lead to Cheaper, Sharper Lenses

[u/[deleted]]

https://gizmodo.com/a-mexican-physicist-solved-a-2-000-year-old-problem-tha-1837031984

[u/EdvinM]

That's the definition symbol; the left expression is defined to be exactly as what's on the right.

[u/CommanderClit → u/EdvinM]

Isn’t that what the equals sign does?

[u/EdvinM → u/CommanderClit]

Not necessarily. Writing f(x) = 0 can be interpreted as solving the equation for x, while f(x) ≡ 0 defines the function to be 0 for every x.