Theorem errel 6775

Description: An equivalence relation is a relation. (Contributed by Mario Carneiro, 12-Aug-2015.)

Assertion

Ref	Expression
errel	⊢ (𝑅 Er 𝐴 → Rel 𝑅)

Proof of Theorem errel

Step	Hyp	Ref	Expression
1		df-er 6766	. 2 ⊢ (𝑅 Er 𝐴 ↔ (Rel 𝑅 ∧ dom 𝑅 = 𝐴 ∧ (◡𝑅 ∪ (𝑅 ∘ 𝑅)) ⊆ 𝑅))
2	1	simp1bi 1039	1 ⊢ (𝑅 Er 𝐴 → Rel 𝑅)

Syntax hints:   → wi 4   = wceq 1398   ∪ cun 3208   ⊆ wss 3210  ^◡ccnv 4747  dom cdm 4748   ∘ ccom 4752  Rel wrel 4753   Er wer 6763

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106

This theorem depends on definitions:  df-bi 117  df-3an 1007  df-er 6766

This theorem is referenced by:  ercl  6777  ersym  6778  ertr  6781  ercnv  6787  erssxp  6789  erth  6812  iinerm  6840  eqg0el  13938