maxima has logic package, written in 2009 by alexey beshenov. it lives in share/logic which is also where the texi docs are. it's included with the op version,

maxima has logic package, written in 2009 by alexey beshenov. it lives in share/logic which is also where the texi docs are. it's included with the op version, load(logic); logic_simp (a or (b or false or (a or b))); characteristic_vector (a xor b); zhegalkin_form ((a implies b) or c); e : ((a or b) xor c) and d$ logic_equiv (e, zhegalkin_form (e)); logic_diff (a or b or c, a); demorgan (boolean_form (a nor b nor c)); etc. there's more stuff in docs