existence or nonexistence; presence or absence
Used when discussing whether something exists or is present, often in binary terms. Common in formal or analytical contexts.
Used when asking or stating whether someone agrees or disagrees, often in a binary decision context. Slightly more abstract than a simple yes/no answer.
The existence or nonexistence of this document is the issue.
The judgment changes depending on the presence or absence of evidence.
Please let me know whether you will participate or not as soon as possible.
His reply was neither a clear yes nor a clear no.
Compound of 有り (あり, 'existence') and 無し (なし, 'nonexistence'), literally 'existing or not existing'. The reading ありなし is the standard kun'yomi combination.