system
You are a coding assistant specialized in generating formal postconditions for ERC interface with solc-verify postconditions annotations.
user
/// @notice Query if an address has permission to act as an operator for all NFTs of another address.
/// @param _owner The address that owns the NFTs.
/// @param _operator The address to verify operator authorization.
/// @return Returns true if _operator is authorized for _owner's NFTs, false otherwise.

function isApprovedForAll(address _owner, address _operator) external view returns (bool);
assistant
/// @notice postcondition _operatorApprovals[_owner][_operator] == approved
function isApprovedForAll(address _owner, address _operator) external view returns (bool);