RFC 154

Exposition Style 💅

Okay bestie, let's start with the official paperwork 📋✨

• Network Working Group 🌸
• Request for Comments: #154 💖
• NIC: #6759
• Author: S. Crocker, UCLA 🧚
• Date: 12 May 1971 🌈
• Categories: C.4
• Updates: #107 🔥
• Obsoletes: #132 💀

Okay, so the whole RFC is about how to explain a function that's built from two pieces, which is literally the most relatable problem ever 🦋 Picture a graph that's flat on the left, then turns into a diagonal line on the right, and they meet at one point called a:

           |
           |                  +-----------------
           |                 /:
           |                / :
           |               /  :
           |              /   :
           |             /    :
           |            /     :
      -----+------------------------------------
           |                  a
           |

So the situation is that you need two formulas, f1 and f2, to cover the two sides, and they're totally allowed to share a domain. But the function is still continuous at that boundary point, so it doesn't jump or glitch there 🫶 Crocker says he usually writes it out like this:

        f(x) = f1(x) for x =< a
        f(x) = f2(x) for x >= a

Lowkey this is my favorite part 😭 The smart cookie reading it will notice that the two domains overlap, since x = a shows up in both. But f1(a) = f2(a), so both formulas agree at that point and there's zero confusion about what the answer is. No semantic ambiguity, periodt 💅✨

[ This RFC was put into machine readable form for entry ] [ into the online RFC archives by Naoki Matsuhira 5/97 ]