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Metamath Proof Explorer

Theorem elicc1

Description: Membership in a closed interval of extended reals. (Contributed by NM, 24-Dec-2006) (Revised by Mario Carneiro, 3-Nov-2013)

		Ref	Expression
	Assertion	elicc1	$⊢ (A \in ℝ^{} \land B \in ℝ^{}) \to (C \in [A, B] \leftrightarrow (C \in ℝ^{*} \land A \leq C \land C \leq B))$

Step	Hyp	Ref	Expression
1		df-icc	$⊢ [.] = (x \in ℝ^{}, y \in ℝ^{} ⟼ \{z \in ℝ^{*} \| (x \leq z \land z \leq y)\})$
2	1	elixx1	$⊢ (A \in ℝ^{} \land B \in ℝ^{}) \to (C \in [A, B] \leftrightarrow (C \in ℝ^{*} \land A \leq C \land C \leq B))$