Theorem ertr2d 8688

Description: A transitivity relation for equivalences. (Contributed by Mario Carneiro, 9-Jul-2014.)

Hypotheses

Ref	Expression
ersymb.1	⊢ (𝜑 → 𝑅 Er 𝑋)
ertrd.5	⊢ (𝜑 → 𝐴𝑅𝐵)
ertrd.6	⊢ (𝜑 → 𝐵𝑅𝐶)

Assertion

Ref	Expression
ertr2d	⊢ (𝜑 → 𝐶𝑅𝐴)

Proof of Theorem ertr2d

Step	Hyp	Ref	Expression
1		ersymb.1	. 2 ⊢ (𝜑 → 𝑅 Er 𝑋)
2		ertrd.5	. . 3 ⊢ (𝜑 → 𝐴𝑅𝐵)
3		ertrd.6	. . 3 ⊢ (𝜑 → 𝐵𝑅𝐶)
4	1, 2, 3	ertrd 8687	. 2 ⊢ (𝜑 → 𝐴𝑅𝐶)
5	1, 4	ersym 8683	1 ⊢ (𝜑 → 𝐶𝑅𝐴)

Syntax hints:   → wi 4   class class class wbr 5107   Er wer 8668

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2008  ax-8 2111  ax-9 2119  ax-ext 2701  ax-sep 5251  ax-nul 5261  ax-pr 5387

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3an 1088  df-tru 1543  df-fal 1553  df-ex 1780  df-sb 2066  df-clab 2708  df-cleq 2721  df-clel 2803  df-ral 3045  df-rex 3054  df-rab 3406  df-v 3449  df-dif 3917  df-un 3919  df-ss 3931  df-nul 4297  df-if 4489  df-sn 4590  df-pr 4592  df-op 4596  df-br 5108  df-opab 5170  df-xp 5644  df-rel 5645  df-cnv 5646  df-co 5647  df-er 8671

This theorem is referenced by:  pi1xfrcnvlem  24956