Theorem entr3i

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

	Ref	Expression
Hypotheses	entr3i.1	$$⊢A\approx B$$
	entr3i.2	$$⊢A\approx C$$
Assertion	entr3i	$$⊢B\approx C$$

Proof

Step	Hyp	Ref	Expression
1		entr3i.1	$$⊢A\approx B$$
2		entr3i.2	$$⊢A\approx C$$
3	1	ensymi	$$⊢B\approx A$$
4	3 2	entri	$$⊢B\approx C$$