A⊂B means A is a subset of B

A⊆B means A is a proper subset of B

Formula, Expression and Equation mean the same thing

An algorithm is intractable only if it is NP hard

Two things are similar if they are indistinguishable with regard to some criteria.

The details of the proof are important to the reader.

Steps in the logic of a proof should be simple so that the reader can understand them easily.

Numbering is unnecessary in a paper where only a few theorems and propositions are found.

Using diagrams to convey your argument in a proof can increase its clarity.

Numbering allows reference within the paper ad simplifies discussion of the paper in later sections.

[a,b) is the range a < r ≤ b

m, ........, n represents all integers between m and n exclusive.

"2,4,6,8, ......." would be assumed to be the sequence of positive even numbers.

It is necessary to state both lower and upper bound if the sequence is finite.

The expression 1 ≤ i ≤ 6 should be replaced by i = 1, .......6 if it's not clear that i should be an integer.

Some mathematical characters from other alphabets

have a superficial resemblance to more familiar symbols

and can cause confusion

Characters of the Greek alphabet are widely used

to denote variables and mathematical quantities.

The symbol for rho is “𝜏”

The proportional symbol is often confused with alpha symbol.

epsilon is often confused with the letter "e" and "∈ element of " symbol.

Symbols used in a paper should be familiar to the reader.

≈, ~, and ≃ are used to mean approximately equal to.

You should write "a is less than or equal to b" to represent "a<=b".

≅ means congruent to.

Symbols for floor(⌊ ⌋) and ceiling(⌈ ⌉) are mistakenly replaced with square brackets([ ]) in typesetting.