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Metamath Proof Explorer


Theorem entr3i

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

Ref Expression
Hypotheses entr3i.1 A B
entr3i.2 A C
Assertion entr3i B C

Proof

Step Hyp Ref Expression
1 entr3i.1 A B
2 entr3i.2 A C
3 1 ensymi B A
4 3 2 entri B C