<Tr> <Th> Category </Th> </Tr> <Tr> <Td> * </Td> <Td> ∗ (\ displaystyle * \! \,) </Td> <Td> convolution convolution; convolved with functional analysis </Td> <Td> f ∗ g means the convolution of f and g . </Td> <Td> (f ∗ g) (t) = ∫ 0 t f (τ) g (t − τ) d τ (\ displaystyle (f * g) (t) = \ int _ (0) ^ (t) f (\ tau) g (t - \ tau) \, d \ tau). </Td> </Tr> <Tr> <Td> complex conjugate conjugate complex numbers </Td> <Td> z means the complex conjugate of z . (z _̄ (\ displaystyle (\ bar (z))) can also be used for the conjugate of z, as described below .) </Td> <Td> (3 + 4 i) ∗ = 3 − 4 i (\ displaystyle (3 + 4i) ^ (\ ast) = 3 - 4i). </Td> </Tr> <Tr> <Td> group of units the group of units of ring theory </Td> <Td> R consists of the set of units of the ring R, along with the operation of multiplication . This may also be written R as described above, or U (R). </Td> <Td> (Z / 5 Z) ∗ = ((1), (2), (3), (4)) ≅ C 4 (\ displaystyle (\ begin (aligned) (\ mathbb (Z) / 5 \ mathbb (Z)) ^ (\ ast) & = \ ((1), (2), (3), (4) \) \ \ & \ cong \ mathrm (C) _ (4) \ \ \ end (aligned))) </Td> </Tr>

What does the triangle symbol mean in calculus