Is it a Jordan curve? code-golf geometry Input An expression in t (or θ or ϑ if you prefer instead of t) of the form a+bf(ct) where a, b, and c are integers and f is sin or cos. (The + sign is of course absent if b is negative. If b = 0, you may assume the second term is not omitted, or is omi...

For many code golf questions, we allow functions as answers. What exactly does it mean for some code to be a valid submission as a function? This question came up during a discussion on built-ins, but is a separate discussion from that one. Here are some examples in Python, where I'm not sure w...

It is well-known that there are bijections between ℤ² and the positive integers. Your task is to write code defining such a bijection in your programming language of choice, plus a correctness check (see below) with the smallest number of characters for the function definitions. The solution mu...

In the examples below, A and B will be 2-by-2 matrices, and the matrices are one-indexed. A Kronecker product has the following properties: A⊗B = A(1,1)*B A(1,2)*B A(2,1)*B A(2,2)*B = A(1,1)*B(1,1) A(1,1)*B(1,2) A(1,2)*B(1,1) A(1,2)*B(1,2) A(1,1)*B(2,1) A(1,...