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$$\text{Output}_i = \begin{cases} \text{true} & \text{if } A_i < B_i \\ \text{false} & \text{if } A_i \geq B_i \\ \text{null} & \text{if } A_i \text{ or } B_i \text{ is missing} \end{cases}$$

The Less Than module compares two numeric series element-wise and outputs true wherever the first value is smaller than the second.

A	B	A < B
5	10	true
10	10	false
15	10	false
-5	-2	true

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Strict Inequality

⚠️ Important: This is a strict comparison. Values that are exactly equal return false.

A	B	A < B
10	10	false

For inclusive comparison where equal values also return true, use the LSTE (≤) module.

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Missing Data

If either value is missing (null) at a position — a data gap or a closed-market day — the comparison there is undeterminable and the result is null, not false. A false is a real statement ("A is not below B"); the module never fakes one from a gap.

A	B	A < B
5	null	null
null	10	null
null	null	null

Comparing two real numbers is always well defined, so nulls in the output come only from missing inputs — there is no mathematically undefined case for this module.

In live execution the module returns exactly one datapoint — the newest position — which is null when either input is missing there.

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Input Alignment

When inputs have different lengths or frequencies, Systemic automatically aligns them:

Scenario	Behavior
Different lengths	Shorter series is padded by repeating its last value
Different frequencies	Lower-frequency series is upsampled to match
Constant vs series	Constant is broadcast to all time points

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Practical Example

Oversold detection: Check if RSI < 30 to identify oversold conditions. Connect RSI output to the first input and set the second input to the constant 30.

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Related Modules

• LSTE (≤) — Less than or equal (includes boundary)
• GTR (>) — Greater than
• GTRE (≥) — Greater than or equal
• EQ (==) — Equality comparison