Title: Therefore sign
Content:  In logical argument and mathematical proof, the therefore sign, , is generally used before a logical consequence, such as the conclusion of a syllogism. The symbol consists of three dots placed in an upright triangle and is read therefore. While it is not generally used in formal writing, it is used in mathematics and shorthand.
Title: Principia Mathematica
Content:  which replaced the two dots following the assertion-sign, thus Example 2, with double, triple, and quadruple dots: stands for Example 3, with a double dot indicating a logical symbol (from volume 1, page 10): stands for where the double dot represents the logical symbol ∧ and can be viewed as having the higher priority as a non-logical single dot. Later in section ✸14, brackets "[ ]" appear, and in sections ✸20 and following, braces "{ }" appear. Whether these symbols have specific meanings or are just for visual clarification is unclear. Unfortunately the single dot (but also ":", ":.", "::", etc.) is also used to symbolise "logical product" (contemporary 
Title: Interpunct
Content:  product is distinct from the cross product. For the scalar product of vectors, only the dot operator is used. Another usage of this symbol in mathematics is with functions, where the dot is used as a placeholder for a function argument, in order to distinguish between the function itself and the value of a function evaluated at a specific point. For example, f(·) denotes the function x ↦ f(x) , and θ(s, a, ·) denotes a partial application, where the first two arguments are fixed and the third varies. The bullet operator,, U+2219, is sometimes used to denote the "AND" relationship in formal logic. In computing, the middle dot is usually displayed (but not printed) to indicate white space in various 
Title: Principia Mathematica
Content:  these outermost parentheses, which enclose an entire formula, are usually suppressed.) The first of the single dots, standing between two propositional variables, represents conjunction. It belongs to the third group and has the narrowest scope. Here it is replaced by the modern symbol for conjunction "∧", thus The two remaining single dots pick out the main connective of the whole formula. They illustrate the utility of the dot notation in picking out those connectives which are relatively more important than the ones which surround them. The one to the left of the "⊃" is replaced by a pair of parentheses, the right one goes where the dot is and the 
Title: Interpunct
Content:  may be used as a decimal marker. The centered dot can be used when multiplying units, as in m · kg · s−2 for the newton expressed in terms of SI base units. However, when the decimal point is used as the decimal marker, as in the United States, the use of a centered dot for the multiplication of numbers or values of quantities is discouraged. In mathematics, a small middle dot can be used to represent product; for example, x ∙ y for the product of x and y. When dealing with scalars, it is interchangeable with the multiplication sign, such that x ⋅ y means the same thing as x × y . However, when dealing with vectors, the 
Title: English punctuation
Content:  with the same letters as the full word. Another use of this character, as the decimal point, is found in mathematics and computing (where it is often nicknamed the "dot"), dividing whole numbers from decimal fractions, as in 2,398.45. In many languages, the roles of the comma and decimal point are reversed, with the comma serving as the decimal separator and the dot used as a thousands separator (though a thin space is sometimes used for the latter purpose, especially in technical writing, regardless what the decimal separator is). In computing, the dot is used as a delimiter more broadly, as site and file names ("wikipedia.org", "192.168.0.1." "document.txt"), and serves special functions in various programming and scripting languages.
Title: Ellipsis
Content:  The most common character corresponding to an ellipsis is called 3-ten rīdā ("3-dot leaders", …). 2-ten rīdā exists as a character, but it is used less commonly. In writing, the ellipsis consists usually of six dots (two 3-ten rīdā characters, ……). Three dots (one 3-ten rīdā character) may be used where space is limited, such as in a header. However, variations in the number of dots exist. In horizontally written text the dots are commonly vertically centered within the text height (between the baseline and the ascent line), as in the standard Japanese Windows fonts; in vertically written text the dots are always centered horizontally. As the Japanese word for dot is pronounced "ten", the dots are colloquially called "ten-ten-ten" (てんてんてん, akin to the English 
Title: Ellipsis
Content:  The ellipsis, , or (as a single glyph) , also known informally as dot-dot-dot, is a series of (usually three) dots that indicates an intentional omission of a word, sentence, or whole section from a text without altering its original meaning. The word (plural ellipses) originates from the, élleipsis meaning 'leave out'. Opinions differ as to how to render ellipses in printed material. According to The Chicago Manual of Style, it should consist of three periods, each separated from its neighbor by a non-breaking space:. According to the AP Stylebook, the periods should be rendered with no space between them:. A third option is to use the Unicode character U+2026.
Title: Principia Mathematica
Content:  ":.", "::". However the position of the matching right or left parenthesis is not indicated explicitly in the notation but has to be deduced from some rules that are complex and at times ambiguous. Moreover, when the dots stand for a logical symbol ∧ its left and right operands have to be deduced using similar rules. First one has to decide based on context whether the dots stand for a left or right parenthesis or a logical symbol. Then one has to decide how far the other corresponding parenthesis is: here one carries on until one meets either a larger number of dots, or the same number of dots next 
Title: Full stop
Content:  start with a dot as hidden. This means that they are not displayed or listed to the user by default. In Unix-like systems and Microsoft Windows, the dot character represents the working directory of the file system. Two dots represent the parent directory of the working directory. Bourne shell-derived command-line interpreters, such as sh, ksh , and bash , use the dot as a command to read a file and execute its content in the running interpreter. (Some of these also offer source as a synonym, based on that usage in the C-shell.) Versions of software are often denoted with the style x.y.z (or more), where x is a major release, y is a mid-cycle enhancement release and z is a patch level designation, but actual usage is entirely vendor specific.

Question: what do the 3 dots mean in math?
Answer: therefore sign.
the therefore sign.