You are correct sir, e.g., tensor analysis for general relativity, and functional analysis for quantum mechanics.
Late one night a policeman spots a slightly tipsy man bent over under a street light, looking for something. The policeman says "Have you lost something, sir ?" The man says "Yes, I lost my keys." The policeman say "Are you sure you lost them here?" The man says, "No, I lost them over there, (pointing into the dark) but the light is here."