The Church-Turing thesis applies to partial functions on the same grounds as to total functions (§ 41).

We are always passing the Rubicon, or being called upon to see somebody else pass it. Considering how often it has been passed, the Rubicon ought to be as well bridged as the Thames. … Looking back a few years, we find that that heaven-born minister, Pitt [i.e., William Pitt the Younger], crossed the Rubicon time after time; and while he was crossing it, [Napoleon] Buonaparte was constantly crossing it also. Later, our Wellington crossed the Rubicon when he marched against the French in the Peninsula.

The ‘white-tailed’ kites in the genus Elanus (‘kite’) are small, gull-like, grey-and-white hawks with black forewing patches and varying amounts of black on the underwings.

Westward along Lancaster Avenue, among the stone walls and broad driveways of imposing old houses—their lawns dappled with the shade of ambering maples and dusty, bark-peeled sycamores