sum

n 1: a quantity of money; "he borrowed a large sum"; "the amount

he had in cash was insufficient" [syn: {sum of money}, {amount},

{amount of money}]

2: a quantity obtained by addition [syn: {amount}, {total}]

3: the final aggregate; "the sum of all our troubles did not

equal the misery they suffered" [syn: {sum total}]

4: the choicest or most essential or most vital part of some

idea or experience: "the gist of the prosecutor's

argument"; "the nub of the story" [syn: {kernel}, {substance},

{core}, {center}, {essence}, {gist}, {heart}, {inwardness},

{marrow}, {meat}, {nub}, {pith}, {nitty-gritty}]

5: the whole [syn: {total}, {totality}, {aggregate}]

6: a set containing all and only the members of two or more

given sets; "let C be the union of the sets A and B" [syn:

{union}, {join}]

v : determine the sum of; "Add all the people in this town to

those of the neighboring town" [syn: {total}, {tot}, {tot

up}, {sum up}, {summate}, {tote up}, {add}, {add together},

{tally}, {add up}]

sum

1. In {domain theory}, the sum A : B of two {domain}s

contains all elements of both domains, modified to indicate

which part of the union they come from, plus a new {bottom}

element. There are two constructor functions associated with

the sum:

inA : A -> A:B inB : B -> A:B

inA(a) ◦ (0,a) inB(b) ◦ (1,b)

and a disassembly operation:

case d of {isA(x) -> E1; isB(x) -> E2}

This can be generalised to arbitrary numbers of domains.

See also {smash sum}, {disjoint union}.

2. A {Unix} utility to calculate a 16-bit {checksum} of

the data in a file. It also displays the size of the file,

either in {kilobyte}s or in 512-byte blocks. The checksum may

differ on machines with 16-bit and 32-bit ints.

{Unix manual page}: sum(1).

(1995-03-16)