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In particular, if there is a Content Dictionary Group whose name is, for example, `math' containing Content Dictionaries named `math1', `math2' etc., then you should not name a derived Content Dictionary `mathN' where N is an integer. However you are free to name it `private_mathN' or some such. This is because the names `mathN' may be used by the OpenMath Society for future extensions. c) The derived work is distributed under terms that allow the compilation of derived works, but keep paragraphs a) and b) intact. The simplest way to do this is to distribute the derived work under the OpenMath license, but this is not a requirement. If you have questions about this license please contact the OpenMath society at http://www.openmath.org. arith1 http://www.openmath.org/cd http://www.openmath.org/cd/arith1.ocd 2006-03-30 official 2004-03-30 3 0 This CD defines symbols for common arithmetic functions. lcm application The symbol to represent the n-ary function to return the least common multiple of its arguments. lcm(a,b) = a*b/gcd(a,b) for all integers a,b | There does not exist a c>0 such that c/a is an Integer and c/b is an Integer and lcm(a,b) > c. 0 gcd application The symbol to represent the n-ary function to return the gcd (greatest common divisor) of its arguments. for all integers a,b | There does not exist a c such that a/c is an Integer and b/c is an Integer and c > gcd(a,b). Note that this implies that gcd(a,b) > 0 gcd(6,9) = 3 6 9 3 plus application The symbol representing an n-ary commutative function plus. for all a,b | a + b = b + a unary_minus application This symbol denotes unary minus, i.e. the additive inverse. for all a | a + (-a) = 0 minus application The symbol representing a binary minus function. This is equivalent to adding the additive inverse. for all a,b | a - b = a + (-b) times application The symbol representing an n-ary multiplication function. 1 2 3 4 5 6 7 8 19 22 43 50 for all a,b | a * 0 = 0 and a * b = a * (b - 1) + a for all a,b,c | a*(b+c) = a*b + a*c divide application This symbol represents a (binary) division function denoting the first argument right-divided by the second, i.e. divide(a,b)=a*inverse(b). It is the inverse of the multiplication function defined by the symbol times in this CD. whenever not(a=0) then a/a = 1 power application This symbol represents a power function. The first argument is raised to the power of the second argument. When the second argument is not an integer, powering is defined in terms of exponentials and logarithms for the complex and real numbers. This operator can represent general powering. x\in C implies x^a = exp(a ln x) if n is an integer then x^0 = 1, x^n = x * x^(n-1) 0 1 1 2 3 4 3 37 54 81 118 abs application A unary operator which represents the absolute value of its argument. The argument should be numerically valued. In the complex case this is often referred to as the modulus. for all x,y | abs(x) + abs(y) >= abs(x+y) root application A binary operator which represents its first argument "lowered" to its n'th root where n is the second argument. This is the inverse of the operation represented by the power symbol defined in this CD. Care should be taken as to the precise meaning of this operator, in particular which root is represented, however it is here to represent the general notion of taking n'th roots. As inferred by the signature relevant to this symbol, the function represented by this symbol is the single valued function, the specific root returned is the one indicated by the first CMP. Note also that the converse of the second CMP is not valid in general. x\in C implies root(x,n) = exp(ln(x)/n) for all a,n | power(root(a,n),n) = a (if the root exists!) sum application An operator taking two arguments, the first being the range of summation, e.g. an integral interval, the second being the function to be summed. Note that the sum may be over an infinite interval. This represents the summation of the reciprocals of all the integers between 1 and 10 inclusive. 1 10 1 product application An operator taking two arguments, the first being the range of multiplication e.g. an integral interval, the second being the function to be multiplied. Note that the product may be over an infinite interval. This represents the statement that the factorial of n is equal to the product of all the integers between 1 and n inclusive. 1