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DcasA Dynamic Computer Algebra System is the idea to use identities as rules for manipulation of algebra. Robert Fenichel's developed a system called FAMOUS in the 1970s using LISP which could. A modern system DCAS has been implemented by Martin Johansen called DCAS Ether. The system works by selcting a class of identities based on the form of the input expression. Here are two examples of identity collections, one for basic algebra, the other for boolean algebra. /* Distributivity */ x*(a + b) = a*x + b*x; /* Powers */ (a*b)^c = a^c*b^c; (a^b)^c = a^(b*c); /* add, sub */ solveequ(x, (gfvi(f(x)) + gfve(a(x)) = gfve(b(x)))) = solveequ(x, f = b - a); solveequ(x, (gfvi(f(x)) + gfve(a(x)) + c = gfve(b(x)))) = solveequ(x, f + c = b - a); /* mul, div */ solveequ(x, (gfvi(f(x))*gfve(a(x))*c = gfve(b(x)))) = solveequ(x, f*c = b/a); solveequ(x, gfvi(f(x))*gfve(a(x)) = gfve(b(x))) = solveequ(x, f = b/a); External links Webpages of computer algebra systems *DCAS research
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