Correct grammatical error in README.md

Author: heptaflar

README.md

@@ -18,7 +18,7 @@ treat inputs, outputs, sensitivities, and uncertainties as dynamic tensor‑valu
 objects rather than forcing the uncertainty calculus into a fixed set of
 closed‑form formulas.
 
-The ideas presented here grew out of earlier project-specific implementations
+The concept presented here grew out of earlier project-specific implementations
 of AD-based uncertainty propagation for harmonized satellite calibration
 workflows underpinning fundamental climate data records.