English: In geometry, hedgehogs are the natural geometrical objects that represent the formal differences of convex bodies: given (K,L) an ordered pair of convex bodies in the Euclidean vector space {\displaystyle \mathbb {R} ^{n+1}, there exists one, and only one, hedgehog that represents the formal difference K – L in{\displaystyle \mathbb {R} ^{n+1}.
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