2019-09-02 02:59:40 -0600 received badge ● Nice Question (source) 2019-09-01 12:22:03 -0600 asked a question Vector valued function: unable to convert to symbolic expression This has been giving me quite a headache. It seems that I am unable to create even a simple vector-valued function of multiple variables. For example, the following  F(s,t)=vector([1,s,s*t])  spits out a big traceback ending with TypeError: unable to convert (1, s, s*t) to a symbolic expression. What's going on here? I know I can use substitution instead, but what if I'd prefer a callable function? 2019-02-15 00:29:14 -0600 received badge ● Famous Question (source) 2018-02-28 10:43:21 -0600 received badge ● Notable Question (source) 2017-08-10 08:33:47 -0600 received badge ● Student (source) 2017-07-26 18:02:46 -0600 received badge ● Popular Question (source) 2017-07-21 16:57:36 -0600 commented answer Piecewise Symbolic Function with Conditional Statement There isn't any sort of conditional statement in the above code, which is what my question addresses. 2017-07-21 12:52:38 -0600 asked a question Piecewise Symbolic Function with Conditional Statement I wish to incorporate a conditional Python expression (if ... else ...) in a symbolic function. Suppose I have a piecewise function k(n) defined for n = 1,2,3... as in the following pseudocode: k(n) = 2 if n = 1 n otherwise  I compose this with another function g(x) and wish to integrate the result. For example, f(x)=g(x)/k(n) f(n=...).integrate(x, 0, 1)  How can implement a non-evaluating conditional in a symbolic Sage function?