typo on contact models

Author: simon-lc

docs/src/linearized_friction.md

@@ -16,9 +16,9 @@ $$\text{minimize}_{\beta} \quad [v^T  -v^T] \beta, \\
 \text{subject to} \quad \beta^T \mathbf{1} \leq \mu \gamma, \\
 \beta \geq 0,$$
 
-which satisfies the LCP formulation, is instead solved. Here, the friction cone is linearized (Fig. \ref{friction_cones}) and the friction vector, $\beta \in \mathbf{R}^{4}$, is correspondingly overparameterized and subject to additional non-negative constraints \cite{stewart1996implicit}.
+which satisfies the LCP formulation, is instead solved. Here, the friction cone is linearized and the friction vector, $\beta \in \mathbf{R}^{4}$, is correspondingly overparameterized and subject to additional non-negative constraints.
 
-The optimality conditions of \eqref{mdp_linear} and constraints used in the LCP are:
+The optimality conditions of the above problem and constraints used in the LCP are:
 
 $$[v^T  -v^T]^T + \psi \mathbf{1} - \eta = 0, \\
 \mu \gamma -\beta^T \textbf{1} \geq 0,\\

docs/src/nonlinear_friction.md

@@ -25,7 +25,8 @@ The second-order-cone product is:
 $$\beta \circ \eta = (\beta^T \eta, \beta_{(1)} \eta_{(2:n)} + \eta_{(1)} \beta_{(2:n)}),$$
 
 and,
-$$\mathbf{e} = (1, 0, \dots, 0) \label{soc_identity},$$
+
+$$\mathbf{e} = (1, 0, \dots, 0),$$
 
 is its corresponding identity element. Friction is recovered from the solution: $b = \beta^*_{(2:3)}$. The benefits of this model are increased physical fidelity and fewer optimization variables, without substantial increase in computational cost.