If the validity of an eruv is in doubt (e.g., it is uncertain whether it existed at bein hashmashot), is it valid?
Synopsis
When there is a safek whether an eruv was valid at bein hashmashot, the eruv is valid only if it had an established presumption of kashrut (chazakat kashrut). If there was no prior chazakah — e.g., it is unknown whether the eruv was placed at all — it is invalid.
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