# Symbols, and relationships in mathematics

Keywords:

$\left|a\right|$

 $=$ Equal $\ne$ Not equal $\approx$ Approximately equal Bigger, bigger, or equal. For example $a>b$ : a is bigger than b $<,\le$ Smaller, smaller, or equal Element of, not element of set Subset, proper subset Union of sets, intersection of sets Relative complement Symmetric difference of sets $×$ Cartesian producta, vectorial product $¬$ Logical negation Logical disjunction (or), logical conjunction (and) Logical equivalence, exclusive or (XOR) $⇒$ Logical implication $\forall$ For all $\exists$ There exist $\left|a\right|$ AAbsolute value of number a $\sum _{}$ Summation $\prod _{}$ Product of sequences $!$ Factorial ${\int }_{}$ Indefinite Integrals ${\int }_{a}^{b}$ Definite Integrals $\sphericalangle$ Angle Right angle $\perp$ Perpendicular $\parallel$ Parallel $~$ Similar $\cong$ Coincident mod Remainder after division lim Limit, limes exp Exponential function log, lg, ln Logarithm $\varnothing$ Empty set $\mathrm{ℕ}$ Natural Numbers $\mathrm{ℤ}$ Integers $\mathrm{ℚ}$ Rational Numbers $\mathrm{ℝ}$ Real numbers $\mathrm{ℂ}$ Complex numbers $\infty$ Infinity