This is my project that organize an article a week about what I learned & thought.
・Mendoza line
Mendoza line is the minimum achievement that a person is considered to be enough. Take an example, if a student is brilliant in English, then 110 in TOEFL might be his mendoza line. If he gets the score below 110, his/her friends will be really disappointed.
The origin of this term is from MLB. 1979, there was an infielder called Mario Mendoza.
That season he played for Seattle Mariners, and his batting average lingered around 0.200 during the whole season. So his teammates just made fun of his performance, and invented a term “Mendoza line” to denote this situation, which meant 0.200 is the Mendoza line. If Mario’s batting average fell below 0.200, then he just didn’t reach their expectation.
After few years, this term became viral, and was used in many realms. It is also a common term be used in the daily life.
・Iff
Iff means “if and only if”.
It keeps apearing in the Linear Algebra course and it is used to express some strictly limited situation. In order to simply elaborate it, we can just take some examples to demonstrate the difference between if and iff.
“If the ice cream is strawberry ice cream, then I’ll eat it.”
(I’ll eat the strawberry ice cream, and I might aslo eat the ice cream if there is another flavor.)
“Iff the ice cream is strawberry, then I’ll eat it.”
(I’ll eat the ice cream only when the flavor is strawberry)
The usage of iff abbreviation first appeared in John Kelley’s 1955 book “General Topology”. Although it isn’t immensely used in our daily life, it still a common notation in mathematics and philosophy fields.
・Four-dimensional space
In linear algebra, a four-dimensional space is a concept of sapce which is generated by four linearly independent vectors. It is really hard to imagine in our mind since the sapce we live is literally a three-dimensional space.
In our common recognition, four-dimensional sapce might be three-dimensional sapce combines with the forth dimension “time”. But it is a different concept and sometimes may even be used inappropriately.
Three-dimensional space combines with time, which is also called “Minkowski spacetime”, is a form closely relates with Special Relativity from Albert Einstein. If we just want to express the geometry space which is a higher level world compares with our universe, then it will be like the picture above.
Some people maintain that four-dimensional space exists in quantum state, and can therefore break the limit of time and space. If there are some life in four-dimensional sapce, they might easily defeat us. Just as the fact that we can easily tear a animal drew on paper, which is a two-dimensional space.
People’s intellengence is finite. However, with the growing of Ai technology, perhaps some day we can successfully realize the high-dimensional space. And it will be a great progress for human spirit.