1. <hardware> An electrical conductor.  For distances larger
	than a breadbox, a single line may consist of two electrical
	conductors in twisted, parallel, or concentric arrangement
	used to transport one logical signal.

	By extension, a (usually physical) medium such as an {optical
	fibre} which carries a signal.

	(1995-09-29)

1. Executable code, especially a "pure code" portion shared
	between multiple instances of a program running in a
	{multitasking} {operating system}.

	Compare {English}.

	2. Textual material in the mainstream sense; data in ordinary
	{ASCII} or {EBCDIC} representation (see {flat ASCII}).  "Those
	are text files; you can review them using the editor."

	These two contradictory senses confuse hackers too.

	[{Jargon File}]

	(1995-03-16)

<theory> The least defined element in a given {domain}.

	Often used to represent a non-terminating computation.

	(In {LaTeX}, bottom is written as {\perp}, sometimes with the
	domain as a subscript).

	(1997-01-07)

1. <hardware> the maximum number of {pixels} that can be
	displayed on a {monitor}, expressed as (number of horizontal
	pixels) x (number of vertical pixels), i.e., 1024x768.  The
	ratio of horizontal to vertical resolution is usually 4:3, the
	same as that of conventional television sets.

	2. <logic> A mechanical method for proving statements of
	{first order logic}, introduced by J. A. Robinson in 1965.
	Resolution is applied to two {clauses} in a {sentence}.  It
	eliminates, by {unification}, a {literal} that occurs
	"positive" in one and "negative" in the other to produce a new
	clause, the {resolvent}.

	For example, given the sentence:

		(man(X) => mortal(X))  AND  man(socrates).

	The literal "man(X)" is "negative".  The literal
	"man(socrates)" could be considered to be on the right hand
	side of the degenerate implication

		True => man(socrates)

	and is therefore "positive".  The two literals can be unified
	by the binding X = socrates.

	The {truth table} for the implication function is

		A | B | A => B
		--+---+-------
		F | F |   T
		F | T |   T
		T | F |   F
		T | T |   T

	(The implication only fails if its premise is true but its
	conclusion is false).  From this we can see that

		A => B   ==   (NOT A) OR B

	Which is why the left hand side of the implication is said to
	be negative and the right positive.  The sentence above could
	thus be written

		((NOT man(socrates)) OR mortal(socrates))
		AND
		man(socrates)

	Distributing the AND over the OR gives

		((NOT man(socrates)) AND man(socrates))
		OR
		mortal(socrates) AND man(socrates)

	And since (NOT A) AND A == False, and False OR A == A we can
	simplify to just

		mortal(socrates) AND man(socrates)

	So we have proved the new literal, mortal(socrates).

	Resolution with {backtracking} is the basic control mechanism
	of {Prolog}.

	See also {modus ponens}, {SLD Resolution}.

	3. <networking> {address resolution}.

	(1996-02-09)