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Metamath Proof Explorer


Theorem bln0

Description: A ball is not empty. (Contributed by NM, 6-Oct-2007) (Revised by Mario Carneiro, 12-Nov-2013)

Ref Expression
Assertion bln0 D ∞Met X P X R + P ball D R

Proof

Step Hyp Ref Expression
1 blcntr D ∞Met X P X R + P P ball D R
2 1 ne0d D ∞Met X P X R + P ball D R