11 Logic Symbols Reference

Quick-reference cheatsheet for Boolean / digital-logic operator notation across textbooks, math, and Verilog.

Basic Gates

SymbolOpReads asExample
· ∧ & && *AND"and" / conjunction$x \cdot y$, $x \wedge y$
+ ∨ | ||OR"or" / disjunction$x + y$, $x \vee y$
¬ ~ ! ′ ‾NOT"not" / complement$\overline{x}$, $\neg x$, $x'$

Compound Gates

SymbolOpReads asEquivalent
⊕ ⊻ ^XOR"exclusive or"$x \oplus y = x\overline{y} + \overline{x}y$
⊙ ≡ ↔XNOR"equivalence"$x \odot y = \overline{x \oplus y}$
⊼ ↑NAND"Sheffer stroke"$x \uparrow y = \overline{x \cdot y}$
⊽ ↓NOR"Pierce arrow"$x \downarrow y = \overline{x + y}$

Implication & Set-Style

SymbolOpReads as / Meaning
→ ⊃ ⇒implies"if … then" — $x \to y = \overline{x} + y$
↔ ≡iff"if and only if" (same as XNOR)
intersectionset AND — same effect as · for sets
unionset OR — same effect as + for sets
⊂ ⊆subset"is implied by" — rare in digital logic

Constants & Quantifiers

SymbolMeaning
0 F ⊥false / logic 0 / GND
1 T ⊤true / logic 1 / Vcc
"for all" (used in proofs / SAT)
"there exists"

Verilog / HDL Operators

VerilogOpNotes
&ANDbitwise; &a = AND-reduction
|ORbitwise; |a = OR-reduction
~NOTbitwise complement
^XOR^a = XOR-reduction (parity)
~^ , ^~XNORbitwise equivalence
~&NANDreduction NAND
~|NORreduction NOR
&& || !logical1-bit boolean (returns 0 or 1)
== ===equalitylogical / case (matches X, Z)

Truth-Table & Canonical-Form Notation

SymbolMeaning
Σ m(…)sum of minterms (canonical SOP)
Π M(…)product of maxterms (canonical POS)
D(…) d(…)don't-care set
$m_i$minterm i (product term that is 1 only on row i)
$M_i$maxterm i (sum term that is 0 only on row i)
Convention notes: