latex报错 missing { inserted 不知道怎么修改 错误代码如下

$$\begin{aligned}1+|\sigma(t)|&\geqslant(1-t)(1+|z_{2}|)\$$
$$(1+|\sigma(t)|)^{2} &\geqslant {t(1-t)\left(1+\left|z_{1}\right|\right)\left(1+\left|z_{2}\right|\right)}\$$
$$(1+|\sigma(t)|)^{1-\alpha} &\geqslant(t(1-t)(1+|z_{1}|)(1+|z_{2}|))^{\frac{1-\alpha}{2}}\qquad(1.3)\end{aligned} $$