Topology

by Fillyfoolish

Rating: teen
Tags: Sunset Shimmer, Twilight Sparkle (EqG), Romance, Science Fiction, Equestria Girls, Sex
Length: 1173

Open sets and open kisses.

Open sets and open kisses.

Content warnings:

* Mathematically rigorous puns.
* Lesbianism, of the sciset variety.
* FOME's approval.

Published 2020-10-11 03:00:00 UTC
Last updated 2020-10-11 03:00:00 UTC

Connectedness

Twilight Sparkle and Sunset Shimmer found themselves curled up beside each other, sitting on the edge of Sunset’s bed. As Twilight played with her glasses, infodumping on about point set topology, Sunset merely enjoyed the ambience, radiating in the warmth of the overexcited girl beside her.

“Oh!” Twilight halted her rambling momentarily. “That reminds me of something I meant to give you.” She brushed a lock of hair out of her field of vision and curled it around her ear. “After all, I really like topology, and I really like you.”

“Thanks, I like you too, dork.” Sunset pointed finger guns at Twilight. “Though I am still surprised you of all people like topology so much.”

Twilight scrunched up her face. “What do you mean?”

Sunset bit the inside of her cheek, forming a little dimple on the outside. “It’s the TERFiest branch of mathematics, isn’t it? Reducing things to just their number of holes?”

Twilight shook her head, raised her index finger, and scoffed, “First of all, you did not just insinuate an entire branch of mathematics can be transphobic.”

Sunset placed her hand under chin, lowering her head slightly as she whispered rather loudly, “I think I did.”

Twilight laughed under her breath and raised another finger. “Second, human male and female bodies are topologically equivalent. Same number of holes.”

Sunset poked her thumb under the rim of her underwear over her shirt, raising an eyebrow.

Twilight shook her head. “Topologically speaking. The anatomical difference does not meaningful affect the geometry of the object. Er, person. Note that sex reassignment surgery can be viewed as a continuous deformation, stretching and folding without cutting and pasting.” Twilight grimaced. “Though that’s a weak argument, when said deformation does require a scalpel physically if not geometrically.”

Sunset winced. “I did not need that visual in my head.”

“Sorry.”

“It’s fine.”

Twilight grew pink and hesitated. “Right, that’s enough about my past. Could we talk about you instead?”

Sunset licked her lips. “Your new favourite subject, yes.”

Twilight giggled. “Are you familiar with the concepts of connectedness and completeness?”

“Sure.”

Twilight dropped her eyes to the floor, trying on a small grin as she reached out an open palm. On instinct, Sunset took her hand and mirrored the smile. Revelling in the shared touch, Twilight’s smile only grew. “Then mathematically, you would understand what I mean when I say I feel complete when we’re connected?”

“Yeah, I think I see where this is going, and that’s without using my geode.” With a smirk, she added, “But in the interest of mathematical rigour, I would like to see some proof of your proposition– wait.” She blinked, face draining into an empty trance. “Are you about to make a dirty joke about clopen sets?”

Twilight tilted her head. “While connectedness can certainly be characterized by clopen sets, I don’t see why that would be dirty.”

Sunset fiddled with her thumbs. “Maybe something from my world. Never mind.” A quick smile and a squeeze of Twilight’s hand. “Proceed.”

Twilight bit her lip. “Actually, I was going to leave the connected proposition as an exercise for the reader.”

Sunset raised her eyebrow. “Scripted, huh?”

“Sorry, listener. But I do have a hypothetical question for you.”

“Hypothetical? Uh-huh. Yes?”

“Could a human female body be covered in kisses?”

Sunset wagged her eyebrows. “I believe there are songs written about it, yes.”

“But have you ever proven it?”

Sunset leaned in. “I can always find out now.”

Twilight shivered. “No, that won’t be necessary.”

“Ouch.” Sunset pulled back, bringing her hand to her heart. “Here I was thinking this was all a big setup to kiss your girlfriend.”

Twilight eeped awkwardly. “It was? Is? Will be. Just, let me finish?”

“Gladly.”

“There’s a wonderful proof by considering the compactness of the human form.”

Sunset snickered, cupping the right half of her chest in her hand, eliciting a blush from Twilight as she added, “Careful who you go calling compact, Sparky.”

Twilight sputtered. “C– Compactness, the topological notion that for any open cover of a set there exists a finite subcover.”

Sunset winked. “Someone’s been on Wikipedia.”

“Editing.” Twilight rolled her eyes. “Editing Wikipedia.”

Sunset stuck her tongue out in reply, but Twilight only shook her head quickly and continued, “In a Euclidean space, like the one in which we live, a set is compact if and only if it is closed and bounded. And you, Sunset Shimmer, are closed, seeing as your skin is just as much a part of you as the rest of you, and as for boundedness?”

Twilight tilted her head thirty degrees and closed one eye. She formed L shapes with her hands, bringing her thumbs to her index fingers to form a horizontal window she placed in front of her open eye, acting as a frame of reference. “You fit snugly in a bounding rectangle. Hence you are compact.”

Sunset chuckled. “Ah, so I can be covered in finitely many open sets, wonderful.”

“Something like that.” Twilight danced her fingers by her side, in a desperate attempt to stay focused and not correct the mathematical imprecision of her girlfriend’s paraphrasing. “Anyway, the open interior of a kiss is centered around a point with some nonzero size since a person’s lips have nonzero size, so by kissing every single point on a person’s body, they can be quite literally covered in kisses.”

“Infinitely many kisses.”

“Well, yes.”

“Uncountably infinitely many kisses.”

“Well, also, yes, but–”

Sunset pushed her hair off the front of her shoulders to rest snugly on her back, fluffing out her chest and licking her lips. “I’m down. Let’s get started. With uncountably many left there’s no time like the present.”

Twilight rolled her eyes. “While an excellent use of the next eternity” – Twilight squinted, eyes darting up to the corner – “that won’t be necessary.”

Sunset blew some air through closed lips, producing a trill. “Boo.”

Brushing it off, Twilight reasoned, “Since you can be covered by an set of open kisses, by compactness, you can already be covered by a finite number of kisses.” She raised her arm, tilting her bare wrist parallel to her as if to check a watch dramatically. “So if we use the finite subset instead, we can eventually clear through the backlog.”

“I’m in.” Sunset grinned. “How long will it take? I know you’re a pretty fast kisser, but how many kisses are we talking about?”

“How should I know?” Twilight shrugged. “Compactness gives an existence result. After showing its finite, why would the cardinality of the set in question matter?”

“Can’t you just, uh, count them?”

Twilight swatted her hand. “Don’t be ridiculous. Everyone knows mathematicians can’t count.”

“Right.” Sunset sighed. “I guess if my physics degree will mean anything, I better be the one keeping track then whenever we get started.”

Twilight leaned over and kissed Sunset on the forehead. “Does now work for you?”

Sunset kissed Twilight in the same spot in reply, leaning over to whisper into her ear, “One.”