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Metamath Proof Explorer


Theorem entr2i

Description: A chained equinumerosity inference. (Contributed by NM, 25-Sep-2004)

Ref Expression
Hypotheses entr2i.1 𝐴𝐵
entr2i.2 𝐵𝐶
Assertion entr2i 𝐶𝐴

Proof

Step Hyp Ref Expression
1 entr2i.1 𝐴𝐵
2 entr2i.2 𝐵𝐶
3 1 2 entri 𝐴𝐶
4 3 ensymi 𝐶𝐴