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Description
Graph Theory: In Mathematical Olympiad and CompetitionsIn 1736, the mathematician Euler invented graph theory while solving the Konigsberg seven bridge problem. Over 200 years later, graph theory remains the skeleton content of discrete mathematics, which serves as a theoretical basis for computer science and network information science. This book introduces some basic knowledge and the primary methods in graph theory by many interesting problems and games.
In 1736, the mathematician Euler invented graph theory while solving the Konigsberg seven-bridge problem. Over 200 years later, graph theory remains the skeleton content of discrete mathematics, which serves as a theoretical basis for computer science and network information science. This book introduces some basic knowledge and the primary methods in graph theory by many interesting problems and games.
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★★★★★ 5
Smooth skin without the post-shave itch
I’ve always had issues with my skin feeling super irritated after I shave my legs, so I started applying this Cyperus Rotundus oil right after hopping out of the shower. The quality of the blend is impressive—it’s got jojoba and almond oil too, so it feels very nourishing rather than just sitting on top of the skin. It absorbs quickly enough that I can put on my leggings and head to the gym without feeling like a greaseball.
The functionality as a hair inhibitor is a nice bonus. I’ve noticed the hair on my shins seems to be coming back a bit softer and less stubbly than before. For a 55 ml bottle, the value for money is solid since you only need a few drops to cover a large area. It’s a great find for anyone who deals with that annoying sandpaper feeling a day after waxing. My roommate even started using it on her arms because it’s fragrance-free and doesn't mess with her perfume.
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Reviewed in the United States on April 15, 2026
★★★★★ 5
Lightweight oil that fits into a simple routine
I started using this oil as part of my regular skincare routine, mainly applying it to areas like my arms and face after showering. The texture feels light and spreads easily without leaving a heavy residue. I noticed it absorbs fairly quickly, which makes it convenient for daily use. It also has a mild scent that is not overwhelming. I like that it includes plant based ingredients, and it leaves my skin feeling soft after application.
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Reviewed in the United States on April 30, 2026
★★★★★ 5
Amazing!!
Scent: Unscented, Size: 1.85 Fl Oz (Pack of 1), Scent: Unscented, Size: 1.85 Fl Oz (Pack of 1)
Amazing product! I have a hormone imbalance and am prone to ingrown hairs, pustules, and very coarse hair on my chin, jawline, and neck. Since using this product, my ingrown hairs have decreased significantly. It works well for me as someone with PCOS. It has a very comfortable scent, but it is very light. I don’t notice the smell after I rub it in. It really works and should consistently use.
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Reviewed in the United States on June 2, 2026
★★★★★ 5
soft finish for upper lip and chin area
I pay close attention to fine facial hair, especially around my upper lip and chin area. Under strong lighting, those small hairs can appear more visible, so I have been looking for a gentle way to care for this area without anything harsh or overly complicated. At night, after cleansing my face and completing my basic skincare, I apply this oil as the final step. It feels like a light finishing layer over the skin. I use a very small amount, about one or two drops, warm it between my fingertips, then gently press it onto the upper lip and chin area. There is no stinging sensation, and the scent is very mild, which makes the application feel calm and comfortable. The texture feels lighter than expected. It spreads smoothly and settles quickly without leaving a heavy or greasy film. My skin type leans slightly combination, and in my case it sits well without making the T zone feel overly coated. Even when I follow with a light moisturizer, it layers without pilling and still feels breathable on the skin. After using it regularly every three days in the evening, the change I notice is mainly visual. The fine facial hair looks less pronounced under bright lighting, especially around the upper lip area. The skin surface also appears more even, and when I touch it, it feels smoother and less uneven in texture. These changes feel gradual rather than sudden, becoming more noticeable over time. From a makeup perspective in the morning, my base applies more evenly after cleansing. Foundation tends to sit more smoothly around the chin and upper lip area, without clinging to texture. During humid days, the skin can feel slightly more active in oil balance, but the overall finish still looks even and natural once makeup is applied.
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Reviewed in the United States on April 10, 2026
★★★★★ 5
Good for maintaining clean beard lines
I keep my beard trimmed, but I always have to clean up the edges along my neckline to keep it looking neat. Lately, I've been massaging a few drops of this natural oil into my neck on Tuesday mornings right after I finish shaving at the sink. It feels really soothing on freshly shaved skin, kind of acting like a light daily moisturizer.
The bottle is only 1.85 ounces, but you only need a tiny dab to cover a small area so it should last a while. Over the last month, the stubble along my collar line definitely feels softer, and it takes an extra day or two before it starts looking messy again. If you trim your own facial hair and want to stretch out the time between touching up your neck or cheek lines, this is handy to keep by the mirror.
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Reviewed in the United States on May 21, 2026
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