Metamath Proof Explorer


Theorem entr4i

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

Ref Expression
Hypotheses entr4i.1 𝐴𝐵
entr4i.2 𝐶𝐵
Assertion entr4i 𝐴𝐶

Proof

Step Hyp Ref Expression
1 entr4i.1 𝐴𝐵
2 entr4i.2 𝐶𝐵
3 2 ensymi 𝐵𝐶
4 1 3 entri 𝐴𝐶